Attribute.GetCustomAttributes 方法

定义

命名空间:

System

程序集:

System.Runtime.dll

程序集:

mscorlib.dll

程序集:

netstandard.dll

检索应用于程序集、模块、类型成员或方法参数的自定义属性的数组。

重载

GetCustomAttributes(ParameterInfo, Boolean)	检索应用于方法参数的自定义属性的数组。 参数指定方法参数以及是否搜索方法参数的祖先。
GetCustomAttributes(MemberInfo, Type, Boolean)	检索应用于类型的成员的自定义属性的数组。 参数指定成员、要搜索的自定义属性的类型以及是否搜索成员的祖先。
GetCustomAttributes(ParameterInfo, Type, Boolean)	检索应用于方法参数的自定义属性的数组。 参数指定方法参数、要搜索的自定义属性的类型以及是否搜索方法参数的祖先。
GetCustomAttributes(Module, Type, Boolean)	检索应用于模块的自定义属性的数组。 参数指定模块、要搜索的自定义属性的类型以及忽略的搜索选项。
GetCustomAttributes(MemberInfo, Type)	检索应用于类型的成员的自定义属性的数组。 参数指定成员和要搜索的自定义属性的类型。
GetCustomAttributes(Assembly, Type, Boolean)	检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集、要搜索的自定义属性的类型以及忽略的搜索选项。
GetCustomAttributes(Module, Type)	检索应用于模块的自定义属性的数组。 参数指定模块和要搜索的自定义属性的类型。
GetCustomAttributes(ParameterInfo, Type)	检索应用于方法参数的自定义属性的数组。 参数指定方法参数和要搜索的自定义属性的类型。
GetCustomAttributes(MemberInfo, Boolean)	检索应用于类型的成员的自定义属性的数组。 参数指定成员、要搜索的自定义属性的类型以及是否搜索成员的祖先。
GetCustomAttributes(Assembly, Type)	检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集和要搜索的自定义属性的类型。
GetCustomAttributes(Assembly, Boolean)	检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集及忽略的搜索选项。
GetCustomAttributes(ParameterInfo)	检索应用于方法参数的自定义属性的数组。 参数指定方法参数。
GetCustomAttributes(Module)	检索应用于模块的自定义属性的数组。 参数指定模块。
GetCustomAttributes(MemberInfo)	检索应用于类型的成员的自定义属性的数组。 参数指定成员。
GetCustomAttributes(Assembly)	检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集。
GetCustomAttributes(Module, Boolean)	检索应用于模块的自定义属性的数组。 参数指定模块及忽略的搜索选项。

GetCustomAttributes(ParameterInfo, Boolean)

检索应用于方法参数的自定义属性的数组。 参数指定方法参数以及是否搜索方法参数的祖先。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::ParameterInfo ^ element, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.ParameterInfo element, bool inherit);

static member GetCustomAttributes : System.Reflection.ParameterInfo * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As ParameterInfo, inherit As Boolean) As Attribute()

参数

element

ParameterInfo

一个从 ParameterInfo 类派生的对象，该类描述类成员的参数。

inherit

Boolean

如果为 true，则指定还在 element 的祖先中搜索自定义属性。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentException

element 的 Member 属性为 null。

ArgumentNullException

element 为 null。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesParameterInfo。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

namespace CustAttrs5CS
{
   public ref class AClass
   {
   public:
      void ParamArrayAndDesc(
         // Add ParamArray and Description attributes.
         [Description("This argument is a ParamArray")]
         array<Int32>^args )
      {}
   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the method.
         MethodInfo^ mInfo = clsType->GetMethod( "ParamArrayAndDesc" );
         if ( mInfo != nullptr )
         {
            // Get the parameter information.
            array<ParameterInfo^>^pInfo = mInfo->GetParameters();
            if ( pInfo != nullptr )
            {
               // Iterate through all the attributes for the parameter.
               System::Collections::IEnumerator^ myEnum4 = Attribute::GetCustomAttributes( pInfo[ 0 ] )->GetEnumerator();
               while ( myEnum4->MoveNext() )
               {
                  Attribute^ attr = safe_cast<Attribute^>(myEnum4->Current);

                  // Check for the ParamArray attribute.
                  if ( attr->GetType() == ParamArrayAttribute::typeid )
                                    Console::WriteLine( "Parameter {0} for method {1} "
                  "has the ParamArray attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                  // Check for the Description attribute.
                  else

                  // Check for the Description attribute.
                  if ( attr->GetType() == DescriptionAttribute::typeid )
                  {
                     Console::WriteLine( "Parameter {0} for method {1} "
                     "has a description attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                     Console::WriteLine( "The description is: \"{0}\"", (dynamic_cast<DescriptionAttribute^>(attr))->Description );
                  }
               }
            }
         }
      }
   };
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

using System;
using System.Reflection;
using System.ComponentModel;

namespace CustAttrs5CS {
    public class AClass {
        public void ParamArrayAndDesc(
            // Add ParamArray (with the keyword) and Description attributes.
            [Description("This argument is a ParamArray")]
            params int[] args)
        {}
    }

    class DemoClass {
        static void Main(string[] args) {
            // Get the Class type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for the method.
            MethodInfo mInfo = clsType.GetMethod("ParamArrayAndDesc");
            if (mInfo != null) {
                // Get the parameter information.
                ParameterInfo[] pInfo = mInfo.GetParameters();
                if (pInfo != null) {
                    // Iterate through all the attributes for the parameter.
                    foreach(Attribute attr in
                        Attribute.GetCustomAttributes(pInfo[0])) {
                        // Check for the ParamArray attribute.
                        if (attr.GetType() == typeof(ParamArrayAttribute))
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has the ParamArray attribute.",
                                pInfo[0].Name, mInfo.Name);
                        // Check for the Description attribute.
                        else if (attr.GetType() ==
                            typeof(DescriptionAttribute)) {
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has a description attribute.",
                                pInfo[0].Name, mInfo.Name);
                            Console.WriteLine("The description is: \"{0}\"",
                                ((DescriptionAttribute)attr).Description);
                        }
                    }
                }
            }
        }
    }
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

open System
open System.Reflection
open System.ComponentModel

type AClass() =
    member _.ParamArrayAndDesc(
        // Add ParamArray and Description attributes.
        [<Description "This argument is a ParamArray">]
        [<ParamArray>]
        args: int[]) = ()

// Get the Class type to access its metadata.
let clsType = typeof<AClass>

// Get the type information for the method.
let mInfo = clsType.GetMethod "ParamArrayAndDesc"
if mInfo <> null then
    // Get the parameter information.
    let pInfo = mInfo.GetParameters()
    if pInfo <> null then
        // Iterate through all the attributes for the parameter.
        for attr in Attribute.GetCustomAttributes pInfo[0] do
            match attr with 
            // Check for the ParamArray attribute.
            | :? ParamArrayAttribute ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has the ParamArray attribute."
                                
            // Check for the Description attribute.
            | :? DescriptionAttribute as attr ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has a description attribute."
                printfn $"The description is: \"{attr.Description}\""
            | _ -> ()

// Output:
// Parameter args for method ParamArrayAndDesc has a description attribute.
// The description is: "This argument is a ParamArray"
// Parameter args for method ParamArrayAndDesc has the ParamArray attribute.

Imports System.Reflection
Imports System.ComponentModel

Module DemoModule
    Public Class AClass
        ' Add Description and ParamArray (with the keyword) attributes.
        Public Sub ParamArrayAndDesc( _
            <Description("This argument is a ParamArray")> _
            ByVal ParamArray args() As Integer)
        End Sub
    End Class

    Sub Main()
        ' Get the Class type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for the method.
        Dim mInfo As MethodInfo = clsType.GetMethod("ParamArrayAndDesc")
        ' Get the Parameter information for the method.
        Dim pInfo() As ParameterInfo = mInfo.GetParameters()
        Dim attr As Attribute
        ' Iterate through each attribute of the parameter.
        For Each attr In Attribute.GetCustomAttributes(pInfo(0))
            ' Check for the ParamArray attribute.
            If TypeOf attr Is ParamArrayAttribute Then
                ' Convert the attribute to access its data.
                Dim paAttr As ParamArrayAttribute = _
                    CType(attr, ParamArrayAttribute)
                Console.WriteLine("Parameter {0} for method {1} has the " + _
                    "ParamArray attribute.", pInfo(0).Name, mInfo.Name)
            ' Check for the Description attribute.
            ElseIf TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Parameter {0} for method {1} has a description " + _
                    "attribute. The description is:", pInfo(0).Name, mInfo.Name)
                Console.WriteLine(descAttr.Description)
            End If
        Next
    End Sub
End Module

' Output:
' Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
' Parameter args for method ParamArrayAndDesc has a description attribute. The description is:
' This argument is a ParamArray

注解

如果 element 表示派生类型的方法中的参数，则返回值包括应用于重写基方法中同一参数的可继承自定义属性。

GetCustomAttributes(MemberInfo, Type, Boolean)

检索应用于类型的成员的自定义属性的数组。 参数指定成员、要搜索的自定义属性的类型以及是否搜索成员的祖先。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element, Type ^ type, bool inherit);

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element, Type ^ attributeType, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element, Type type, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element, Type attributeType, bool inherit);

static member GetCustomAttributes : System.Reflection.MemberInfo * Type * bool -> Attribute[]

static member GetCustomAttributes : System.Reflection.MemberInfo * Type * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As MemberInfo, type As Type, inherit As Boolean) As Attribute()

Public Shared Function GetCustomAttributes (element As MemberInfo, attributeType As Type, inherit As Boolean) As Attribute()

参数

element

MemberInfo

一个从 MemberInfo 类派生的对象，该类描述类的构造函数、事件、字段、方法或属性成员。

typeattributeType

Type

要搜索的自定义属性的类型或基类型。

inherit

Boolean

如果为 true，则指定还在 element 的祖先中搜索自定义属性。

返回

Attribute[]

一个 Attribute 数组，包含应用于 type 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 type 为 null。

ArgumentException

type 不是从 Attribute 派生的。

NotSupportedException

element 不是构造函数、方法、属性、事件、类型或字段。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了如何使用 GetCustomAttributes作为 MemberInfo 参数。

using namespace System;
using namespace System::Reflection;
using namespace System::Security;
using namespace System::Runtime::InteropServices;

namespace CustAttrs4CS
{
   // Create a class for Win32 imported unmanaged functions.
   public ref class Win32
   {
   public:

      [DllImport("user32.dll", CharSet = CharSet::Unicode)]
      static int MessageBox( int hWnd, String^ text, String^ caption, UInt32 type );
   };

   public ref class AClass
   {
   public:

      // Add some attributes to the Win32CallMethod.

      [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
      void Win32CallMethod()
      {
         Win32::MessageBox( 0, "This is an unmanaged call.", "Be Careful!", 0 );
      }

   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the Win32CallMethod.
         MethodInfo^ mInfo = clsType->GetMethod( "Win32CallMethod" );
         if ( mInfo != nullptr )
         {
            // Iterate through all the attributes for the method.
            System::Collections::IEnumerator^ myEnum3 = Attribute::GetCustomAttributes( mInfo )->GetEnumerator();
            while ( myEnum3->MoveNext() )
            {
               Attribute^ attr = safe_cast<Attribute^>(myEnum3->Current);

               // Check for the Obsolete attribute.
               if ( attr->GetType() == ObsoleteAttribute::typeid )
               {
                  Console::WriteLine( "Method {0} is obsolete. "
                  "The message is:", mInfo->Name );
                  Console::WriteLine( (dynamic_cast<ObsoleteAttribute^>(attr))->Message );
               }
               // Check for the SuppressUnmanagedCodeSecurity attribute.
               else

               // Check for the SuppressUnmanagedCodeSecurity attribute.
               if ( attr->GetType() == SuppressUnmanagedCodeSecurityAttribute::typeid )
               {
                  Console::WriteLine( "This method calls unmanaged code "
                  "with no security check." );
                  Console::WriteLine( "Please do not use unless absolutely necessary." );
                  AClass^ myCls = gcnew AClass;
                  myCls->Win32CallMethod();
               }
            }
         }
      }
   };
}


/*
 * Output:
 * Method Win32CallMethod is obsolete. The message is:
 * This method is obsolete. Use managed MsgBox instead.
 * This method calls unmanaged code with no security check.
 * Please do not use unless absolutely necessary.
 */

using System;
using System.Reflection;
using System.Security;
using System.Runtime.InteropServices;

namespace CustAttrs4CS
{

    // Define an enumeration of Win32 unmanaged types
    public enum UnmanagedType
    {
        User,
        GDI,
        Kernel,
        Shell,
        Networking,
        Multimedia
    }

    // Define the Unmanaged attribute.
    public class UnmanagedAttribute : Attribute
    {
        // Storage for the UnmanagedType value.
        protected UnmanagedType thisType;

        // Set the unmanaged type in the constructor.
        public UnmanagedAttribute(UnmanagedType type)
        {
            thisType = type;
        }

        // Define a property to get and set the UnmanagedType value.
        public UnmanagedType Win32Type
        {
            get { return thisType; }
            set { thisType = Win32Type; }
        }
    }

    // Create a class for an imported Win32 unmanaged function.
    public class Win32 {
        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        public static extern int MessageBox(int hWnd, String text,
            String caption, uint type);
    }

    public class AClass {
        // Add some attributes to Win32CallMethod.
        [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
        [Unmanaged(UnmanagedType.User)]
        public void Win32CallMethod()
        {
            Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0);
        }
    }

    class DemoClass {
        static void Main(string[] args)
            {
            // Get the AClass type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for Win32CallMethod.
            MethodInfo mInfo = clsType.GetMethod("Win32CallMethod");
            if (mInfo != null)
            {
                // Iterate through all the attributes of the method.
                foreach(Attribute attr in
                    Attribute.GetCustomAttributes(mInfo)) {
                    // Check for the Obsolete attribute.
                    if (attr.GetType() == typeof(ObsoleteAttribute))
                    {
                        Console.WriteLine("Method {0} is obsolete. " +
                            "The message is:",
                            mInfo.Name);
                        Console.WriteLine("  \"{0}\"",
                            ((ObsoleteAttribute)attr).Message);
                    }

                    // Check for the Unmanaged attribute.
                    else if (attr.GetType() == typeof(UnmanagedAttribute))
                    {
                        Console.WriteLine(
                            "This method calls unmanaged code.");
                        Console.WriteLine(
                            String.Format("The Unmanaged attribute type is {0}.",
                                          ((UnmanagedAttribute)attr).Win32Type));
                        AClass myCls = new AClass();
                        myCls.Win32CallMethod();
                    }
                }
            }
        }
    }
}

/*

This code example produces the following results.

First, the compilation yields the warning, "... This method is
obsolete. Use managed MsgBox instead."
Second, execution yields a message box with a title of "Caution!"
and message text of "This is an unmanaged call."
Third, the following text is displayed in the console window:

Method Win32CallMethod is obsolete. The message is:
  "This method is obsolete. Use managed MsgBox instead."
This method calls unmanaged code.
The Unmanaged attribute type is User.

*/

open System
open System.Runtime.InteropServices

// Define an enumeration of Win32 unmanaged types
type UnmanagedType =
    | User = 0
    | GDI = 1
    | Kernel = 2
    | Shell = 3
    | Networking = 4
    | Multimedia = 5

// Define the Unmanaged attribute.
type UnmanagedAttribute(unmanagedType) =
    inherit Attribute()
    
    // Define a property to get and set the UnmanagedType value.
    member val Win32Type = unmanagedType with get, set

// Create a module for an imported Win32 unmanaged function.
module Win32 =
    [<DllImport("user32.dll", CharSet = CharSet.Unicode)>]
    extern int MessageBox(IntPtr hWnd, String text, String caption, uint ``type``)

type AClass() =
    // Add some attributes to Win32CallMethod.
    [<Obsolete "This method is obsolete. Use managed MsgBox instead.">]
    [<Unmanaged(UnmanagedType.User)>]
    member _.Win32CallMethod () =
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0u)

// Get the AClass type to access its metadata.
let clsType = typeof<AClass>
// Get the type information for Win32CallMethod.
let mInfo = clsType.GetMethod "Win32CallMethod"
if mInfo <> null then
    // Iterate through all the attributes of the method.
    for attr in Attribute.GetCustomAttributes mInfo do
        match attr with 
        // Check for the Obsolete attribute.
        | :? ObsoleteAttribute as attr ->
            printfn $"Method {mInfo.Name} is obsolete. The message is:"
            printfn $"  \"{attr.Message}\""

        // Check for the Unmanaged attribute.
        | :? UnmanagedAttribute as attr ->
            printfn "This method calls unmanaged code."
            printfn $"The Unmanaged attribute type is {attr.Win32Type}."
            let myCls = AClass()
            myCls.Win32CallMethod() |> ignore
        | _ -> ()

// This code example produces the following results.
//
// First, the compilation yields the warning, "... This method is
// obsolete. Use managed MsgBox instead."
// Second, execution yields a message box with a title of "Caution!"
// and message text of "This is an unmanaged call."
// Third, the following text is displayed in the console window:

// Method Win32CallMethod is obsolete. The message is:
//   "This method is obsolete. Use managed MsgBox instead."
// This method calls unmanaged code.
// The Unmanaged attribute type is User.

Imports System.Reflection
Imports System.Security
Imports System.Runtime.InteropServices

' Define an enumeration of Win32 unmanaged types
Public Enum UnmanagedType
    User
    GDI
    Kernel
    Shell
    Networking
    Multimedia
End Enum 'UnmanagedType

' Define the Unmanaged attribute.
Public Class UnmanagedAttribute 
             Inherits Attribute

    ' Storage for the UnmanagedType value.
    Protected thisType As UnmanagedType
    
    ' Set the unmanaged type in the constructor.
    Public Sub New(ByVal type As UnmanagedType) 
        thisType = type
    End Sub
    
    ' Define a property to get and set the UnmanagedType value.
    Public Property Win32Type() As UnmanagedType 
        Get
            Return thisType
        End Get
        Set
            thisType = Win32Type
        End Set
    End Property
End Class

' Create a class for an imported Win32 unmanaged function.
Public Class Win32
    <DllImport("user32.dll", CharSet:=CharSet.Unicode)> _
    Public Shared Function MessageBox(ByVal hWnd As Integer, _
                                      ByVal Text As String, _
                                      ByVal caption As String, _
                                      ByVal type As Integer) As Integer
    End Function 'MessageBox
End Class

Public Class AClass
    ' Add some attributes to Win32CallMethod.
    <Obsolete("This method is obsolete. Use managed MsgBox instead."), _
     Unmanaged(UnmanagedType.User)>  _
    Public Sub Win32CallMethod() 
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0)    
    End Sub
End Class

Class DemoClass
    Shared Sub Main(ByVal args() As String) 
        ' Get the AClass type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for Win32CallMethod.
        Dim mInfo As MethodInfo = clsType.GetMethod("Win32CallMethod")
        If Not (mInfo Is Nothing) Then
            ' Iterate through all the attributes of the method.
            Dim attr As Attribute
            For Each attr In  Attribute.GetCustomAttributes(mInfo)
                ' Check for the Obsolete attribute.
                If attr.GetType().Equals(GetType(ObsoleteAttribute)) Then
                    Console.WriteLine("Method {0} is obsolete. The message is:", mInfo.Name)
                    Console.WriteLine("  ""{0}""", CType(attr, ObsoleteAttribute).Message)
                ' Check for the Unmanaged attribute.
                ElseIf attr.GetType().Equals(GetType(UnmanagedAttribute)) Then
                    Console.WriteLine("This method calls unmanaged code.")
                    Console.WriteLine( _
                            String.Format("The Unmanaged attribute type is {0}.", _
                            CType(attr, UnmanagedAttribute).Win32Type))
                    Dim myCls As New AClass()
                    myCls.Win32CallMethod()
                End If
            Next attr
        End If
    End Sub
End Class

'
'This code example produces the following results. 
'
'First, the compilation yields the warning, "... This method is 
'obsolete. Use managed MsgBox instead."
'Second, execution yields a message box with a title of "Caution!" 
'and message text of "This is an unmanaged call." 
'Third, the following text is displayed in the console window:
'
'Method Win32CallMethod is obsolete. The message is:
'  "This method is obsolete. Use managed MsgBox instead."
'This method calls unmanaged code.
'The Unmanaged attribute type is User.
'

注解

返回值包含父级的自定义属性 element （如果 inherit 为 true）。

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回方法、构造函数和类型的安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的.NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(ParameterInfo, Type, Boolean)

检索应用于方法参数的自定义属性的数组。 参数指定方法参数、要搜索的自定义属性的类型以及是否搜索方法参数的祖先。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::ParameterInfo ^ element, Type ^ attributeType, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.ParameterInfo element, Type attributeType, bool inherit);

static member GetCustomAttributes : System.Reflection.ParameterInfo * Type * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As ParameterInfo, attributeType As Type, inherit As Boolean) As Attribute()

参数

element

ParameterInfo

一个从 ParameterInfo 类派生的对象，该类描述类成员的参数。

attributeType

Type

要搜索的自定义属性的类型或基类型。

inherit

Boolean

如果为 true，则指定还在 element 的祖先中搜索自定义属性。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesParameterInfo。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

namespace CustAttrs5CS
{
   public ref class AClass
   {
   public:
      void ParamArrayAndDesc(
         // Add ParamArray and Description attributes.
         [Description("This argument is a ParamArray")]
         array<Int32>^args )
      {}
   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the method.
         MethodInfo^ mInfo = clsType->GetMethod( "ParamArrayAndDesc" );
         if ( mInfo != nullptr )
         {
            // Get the parameter information.
            array<ParameterInfo^>^pInfo = mInfo->GetParameters();
            if ( pInfo != nullptr )
            {
               // Iterate through all the attributes for the parameter.
               System::Collections::IEnumerator^ myEnum4 = Attribute::GetCustomAttributes( pInfo[ 0 ] )->GetEnumerator();
               while ( myEnum4->MoveNext() )
               {
                  Attribute^ attr = safe_cast<Attribute^>(myEnum4->Current);

                  // Check for the ParamArray attribute.
                  if ( attr->GetType() == ParamArrayAttribute::typeid )
                                    Console::WriteLine( "Parameter {0} for method {1} "
                  "has the ParamArray attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                  // Check for the Description attribute.
                  else

                  // Check for the Description attribute.
                  if ( attr->GetType() == DescriptionAttribute::typeid )
                  {
                     Console::WriteLine( "Parameter {0} for method {1} "
                     "has a description attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                     Console::WriteLine( "The description is: \"{0}\"", (dynamic_cast<DescriptionAttribute^>(attr))->Description );
                  }
               }
            }
         }
      }
   };
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

using System;
using System.Reflection;
using System.ComponentModel;

namespace CustAttrs5CS {
    public class AClass {
        public void ParamArrayAndDesc(
            // Add ParamArray (with the keyword) and Description attributes.
            [Description("This argument is a ParamArray")]
            params int[] args)
        {}
    }

    class DemoClass {
        static void Main(string[] args) {
            // Get the Class type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for the method.
            MethodInfo mInfo = clsType.GetMethod("ParamArrayAndDesc");
            if (mInfo != null) {
                // Get the parameter information.
                ParameterInfo[] pInfo = mInfo.GetParameters();
                if (pInfo != null) {
                    // Iterate through all the attributes for the parameter.
                    foreach(Attribute attr in
                        Attribute.GetCustomAttributes(pInfo[0])) {
                        // Check for the ParamArray attribute.
                        if (attr.GetType() == typeof(ParamArrayAttribute))
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has the ParamArray attribute.",
                                pInfo[0].Name, mInfo.Name);
                        // Check for the Description attribute.
                        else if (attr.GetType() ==
                            typeof(DescriptionAttribute)) {
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has a description attribute.",
                                pInfo[0].Name, mInfo.Name);
                            Console.WriteLine("The description is: \"{0}\"",
                                ((DescriptionAttribute)attr).Description);
                        }
                    }
                }
            }
        }
    }
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

open System
open System.Reflection
open System.ComponentModel

type AClass() =
    member _.ParamArrayAndDesc(
        // Add ParamArray and Description attributes.
        [<Description "This argument is a ParamArray">]
        [<ParamArray>]
        args: int[]) = ()

// Get the Class type to access its metadata.
let clsType = typeof<AClass>

// Get the type information for the method.
let mInfo = clsType.GetMethod "ParamArrayAndDesc"
if mInfo <> null then
    // Get the parameter information.
    let pInfo = mInfo.GetParameters()
    if pInfo <> null then
        // Iterate through all the attributes for the parameter.
        for attr in Attribute.GetCustomAttributes pInfo[0] do
            match attr with 
            // Check for the ParamArray attribute.
            | :? ParamArrayAttribute ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has the ParamArray attribute."
                                
            // Check for the Description attribute.
            | :? DescriptionAttribute as attr ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has a description attribute."
                printfn $"The description is: \"{attr.Description}\""
            | _ -> ()

// Output:
// Parameter args for method ParamArrayAndDesc has a description attribute.
// The description is: "This argument is a ParamArray"
// Parameter args for method ParamArrayAndDesc has the ParamArray attribute.

Imports System.Reflection
Imports System.ComponentModel

Module DemoModule
    Public Class AClass
        ' Add Description and ParamArray (with the keyword) attributes.
        Public Sub ParamArrayAndDesc( _
            <Description("This argument is a ParamArray")> _
            ByVal ParamArray args() As Integer)
        End Sub
    End Class

    Sub Main()
        ' Get the Class type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for the method.
        Dim mInfo As MethodInfo = clsType.GetMethod("ParamArrayAndDesc")
        ' Get the Parameter information for the method.
        Dim pInfo() As ParameterInfo = mInfo.GetParameters()
        Dim attr As Attribute
        ' Iterate through each attribute of the parameter.
        For Each attr In Attribute.GetCustomAttributes(pInfo(0))
            ' Check for the ParamArray attribute.
            If TypeOf attr Is ParamArrayAttribute Then
                ' Convert the attribute to access its data.
                Dim paAttr As ParamArrayAttribute = _
                    CType(attr, ParamArrayAttribute)
                Console.WriteLine("Parameter {0} for method {1} has the " + _
                    "ParamArray attribute.", pInfo(0).Name, mInfo.Name)
            ' Check for the Description attribute.
            ElseIf TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Parameter {0} for method {1} has a description " + _
                    "attribute. The description is:", pInfo(0).Name, mInfo.Name)
                Console.WriteLine(descAttr.Description)
            End If
        Next
    End Sub
End Module

' Output:
' Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
' Parameter args for method ParamArrayAndDesc has a description attribute. The description is:
' This argument is a ParamArray

注解

如果 element 表示派生类型的方法中的参数，则返回值包括应用于重写基方法中同一参数的可继承自定义属性。

GetCustomAttributes(Module, Type, Boolean)

检索应用于模块的自定义属性的数组。 参数指定模块、要搜索的自定义属性的类型以及忽略的搜索选项。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Module ^ element, Type ^ attributeType, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.Module element, Type attributeType, bool inherit);

static member GetCustomAttributes : System.Reflection.Module * Type * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As Module, attributeType As Type, inherit As Boolean) As Attribute()

参数

element

Module

一个从 Module 类派生的对象，该类描述可移植的可执行文件。

attributeType

Type

要搜索的自定义属性的类型或基类型。

inherit

Boolean

此参数被忽略，并且不会影响此方法的操作。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesModule。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

// Assign some attributes to the module.
// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:Description("A sample description")];
[module:CLSCompliant(false)];
namespace CustAttrs2CS
{
   ref class DemoClass
   {
   public:
      static void Main()
      {
         Type^ clsType = DemoClass::typeid;

         // Get the Module type to access its metadata.
         Module^ module = clsType->Module;

         // Iterate through all the attributes for the module.
         System::Collections::IEnumerator^ myEnum1 = Attribute::GetCustomAttributes( module )->GetEnumerator();
         while ( myEnum1->MoveNext() )
         {
            Attribute^ attr = safe_cast<Attribute^>(myEnum1->Current);

            // Check for the Description attribute.
            if ( attr->GetType() == DescriptionAttribute::typeid )
                        Console::WriteLine( "Module {0} has the description \"{1}\".", module->Name, (dynamic_cast<DescriptionAttribute^>(attr))->Description );
            // Check for the CLSCompliant attribute.
            else

            // Check for the CLSCompliant attribute.
            if ( attr->GetType() == CLSCompliantAttribute::typeid )
                        Console::WriteLine( "Module {0} {1} CLSCompliant.", module->Name, (dynamic_cast<CLSCompliantAttribute^>(attr))->IsCompliant ? (String^)"is" : "is not" );
         }
      }
   };
}


/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

using System;
using System.Reflection;
using System.ComponentModel;

// Assign some attributes to the module.
[module:Description("A sample description")]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:CLSCompliant(false)]

namespace CustAttrs2CS {
    class DemoClass {
        static void Main(string[] args) {
            Type clsType = typeof(DemoClass);
            // Get the Module type to access its metadata.
            Module module = clsType.Module;

            // Iterate through all the attributes for the module.
            foreach(Attribute attr in Attribute.GetCustomAttributes(module)) {
                // Check for the Description attribute.
                if (attr.GetType() == typeof(DescriptionAttribute))
                    Console.WriteLine("Module {0} has the description " +
                        "\"{1}\".", module.Name,
                        ((DescriptionAttribute)attr).Description);
                // Check for the CLSCompliant attribute.
                else if (attr.GetType() == typeof(CLSCompliantAttribute))
                    Console.WriteLine("Module {0} {1} CLSCompliant.",
                        module.Name,
                        ((CLSCompliantAttribute)attr).IsCompliant ?
                            "is" : "is not");
            }
        }
    }
}

/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

open System
open System.ComponentModel

// Assign some attributes to the module.
[<``module``: Description "A sample description">]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[<``module``: CLSCompliant false>]
do ()

type DemoClass = class end

// Get the Module type to access its metadata.
let ilmodule = typeof<DemoClass>.Module

// Iterate through all the attributes for the module.
for attr in Attribute.GetCustomAttributes ilmodule do
    match attr with
    // Check for the Description attribute.
    | :? DescriptionAttribute as attr ->
        printfn $"Module {ilmodule.Name} has the description \"{attr.Description}\"."
                
    // Check for the CLSCompliant attribute.
    | :? CLSCompliantAttribute as attr ->
        printfn $"""Module {ilmodule.Name} {if attr.IsCompliant then "is" else "is not"} CLSCompliant."""
    | _ -> ()
    
// Output:
// Module CustAttrs2CS.exe is not CLSCompliant.
// Module CustAttrs2CS.exe has the description "A sample description".

Imports System.Reflection
Imports System.ComponentModel

' Give the Module some attributes.
<Module: Description("A sample description")> 

' Make the CLSCompliant attribute False.
' The CLSCompliant attribute is applicable for /target:module.
<Module: CLSCompliant(False)> 

Module DemoModule

    Sub Main()
        ' Get the Module type to access its metadata.
        Dim modType As Reflection.Module = GetType(DemoModule).Module
        Dim attr As Attribute
        ' Iterate through all the attributes for the module.
        For Each attr In Attribute.GetCustomAttributes(modType)
            ' Check for the Description attribute.
            If TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Module {0} has the description ""{1}"".", _
                    modType.Name, descAttr.Description)

            ' Check for the CLSCompliant attribute.
            ElseIf TypeOf attr Is CLSCompliantAttribute Then
                ' Convert the attribute to access its data.
                Dim CLSCompAttr As CLSCompliantAttribute = _
                    CType(attr, CLSCompliantAttribute)
                Dim strCompliant As String
                If CLSCompAttr.IsCompliant Then
                    strCompliant = "is"
                Else
                    strCompliant = "is not"
                End If
                Console.WriteLine("Module {0} {1} CLSCompliant.", _
                    modType.Name, strCompliant)
            End If
        Next
    End Sub
End Module

' Output:
' Module CustAttrs2VB.exe has the description "A sample description".
' Module CustAttrs2VB.exe is not CLSCompliant.

注解

返回值包含父级的自定义属性 element （如果 inherit 为 true）。

GetCustomAttributes(MemberInfo, Type)

检索应用于类型的成员的自定义属性的数组。 参数指定成员和要搜索的自定义属性的类型。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element, Type ^ type);

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element, Type ^ attributeType);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element, Type type);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element, Type attributeType);

static member GetCustomAttributes : System.Reflection.MemberInfo * Type -> Attribute[]

static member GetCustomAttributes : System.Reflection.MemberInfo * Type -> Attribute[]

Public Shared Function GetCustomAttributes (element As MemberInfo, type As Type) As Attribute()

Public Shared Function GetCustomAttributes (element As MemberInfo, attributeType As Type) As Attribute()

参数

element

MemberInfo

一个从 MemberInfo 类派生的对象，该类描述类的构造函数、事件、字段、方法或属性成员。

typeattributeType

Type

要搜索的自定义属性的类型或基类型。

返回

Attribute[]

一个 Attribute 数组，包含应用于 type 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 type 为 null。

ArgumentException

type 不是从 Attribute 派生的。

NotSupportedException

element 不是构造函数、方法、属性、事件、类型或字段。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributeMemberInfo。

using namespace System;
using namespace System::Reflection;
using namespace System::Security;
using namespace System::Runtime::InteropServices;

namespace CustAttrs4CS
{
   // Create a class for Win32 imported unmanaged functions.
   public ref class Win32
   {
   public:

      [DllImport("user32.dll", CharSet = CharSet::Unicode)]
      static int MessageBox( int hWnd, String^ text, String^ caption, UInt32 type );
   };

   public ref class AClass
   {
   public:

      // Add some attributes to the Win32CallMethod.

      [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
      void Win32CallMethod()
      {
         Win32::MessageBox( 0, "This is an unmanaged call.", "Be Careful!", 0 );
      }

   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the Win32CallMethod.
         MethodInfo^ mInfo = clsType->GetMethod( "Win32CallMethod" );
         if ( mInfo != nullptr )
         {
            // Iterate through all the attributes for the method.
            System::Collections::IEnumerator^ myEnum3 = Attribute::GetCustomAttributes( mInfo )->GetEnumerator();
            while ( myEnum3->MoveNext() )
            {
               Attribute^ attr = safe_cast<Attribute^>(myEnum3->Current);

               // Check for the Obsolete attribute.
               if ( attr->GetType() == ObsoleteAttribute::typeid )
               {
                  Console::WriteLine( "Method {0} is obsolete. "
                  "The message is:", mInfo->Name );
                  Console::WriteLine( (dynamic_cast<ObsoleteAttribute^>(attr))->Message );
               }
               // Check for the SuppressUnmanagedCodeSecurity attribute.
               else

               // Check for the SuppressUnmanagedCodeSecurity attribute.
               if ( attr->GetType() == SuppressUnmanagedCodeSecurityAttribute::typeid )
               {
                  Console::WriteLine( "This method calls unmanaged code "
                  "with no security check." );
                  Console::WriteLine( "Please do not use unless absolutely necessary." );
                  AClass^ myCls = gcnew AClass;
                  myCls->Win32CallMethod();
               }
            }
         }
      }
   };
}


/*
 * Output:
 * Method Win32CallMethod is obsolete. The message is:
 * This method is obsolete. Use managed MsgBox instead.
 * This method calls unmanaged code with no security check.
 * Please do not use unless absolutely necessary.
 */

using System;
using System.Reflection;
using System.Security;
using System.Runtime.InteropServices;

namespace CustAttrs4CS
{

    // Define an enumeration of Win32 unmanaged types
    public enum UnmanagedType
    {
        User,
        GDI,
        Kernel,
        Shell,
        Networking,
        Multimedia
    }

    // Define the Unmanaged attribute.
    public class UnmanagedAttribute : Attribute
    {
        // Storage for the UnmanagedType value.
        protected UnmanagedType thisType;

        // Set the unmanaged type in the constructor.
        public UnmanagedAttribute(UnmanagedType type)
        {
            thisType = type;
        }

        // Define a property to get and set the UnmanagedType value.
        public UnmanagedType Win32Type
        {
            get { return thisType; }
            set { thisType = Win32Type; }
        }
    }

    // Create a class for an imported Win32 unmanaged function.
    public class Win32 {
        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        public static extern int MessageBox(int hWnd, String text,
            String caption, uint type);
    }

    public class AClass {
        // Add some attributes to Win32CallMethod.
        [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
        [Unmanaged(UnmanagedType.User)]
        public void Win32CallMethod()
        {
            Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0);
        }
    }

    class DemoClass {
        static void Main(string[] args)
            {
            // Get the AClass type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for Win32CallMethod.
            MethodInfo mInfo = clsType.GetMethod("Win32CallMethod");
            if (mInfo != null)
            {
                // Iterate through all the attributes of the method.
                foreach(Attribute attr in
                    Attribute.GetCustomAttributes(mInfo)) {
                    // Check for the Obsolete attribute.
                    if (attr.GetType() == typeof(ObsoleteAttribute))
                    {
                        Console.WriteLine("Method {0} is obsolete. " +
                            "The message is:",
                            mInfo.Name);
                        Console.WriteLine("  \"{0}\"",
                            ((ObsoleteAttribute)attr).Message);
                    }

                    // Check for the Unmanaged attribute.
                    else if (attr.GetType() == typeof(UnmanagedAttribute))
                    {
                        Console.WriteLine(
                            "This method calls unmanaged code.");
                        Console.WriteLine(
                            String.Format("The Unmanaged attribute type is {0}.",
                                          ((UnmanagedAttribute)attr).Win32Type));
                        AClass myCls = new AClass();
                        myCls.Win32CallMethod();
                    }
                }
            }
        }
    }
}

/*

This code example produces the following results.

First, the compilation yields the warning, "... This method is
obsolete. Use managed MsgBox instead."
Second, execution yields a message box with a title of "Caution!"
and message text of "This is an unmanaged call."
Third, the following text is displayed in the console window:

Method Win32CallMethod is obsolete. The message is:
  "This method is obsolete. Use managed MsgBox instead."
This method calls unmanaged code.
The Unmanaged attribute type is User.

*/

open System
open System.Runtime.InteropServices

// Define an enumeration of Win32 unmanaged types
type UnmanagedType =
    | User = 0
    | GDI = 1
    | Kernel = 2
    | Shell = 3
    | Networking = 4
    | Multimedia = 5

// Define the Unmanaged attribute.
type UnmanagedAttribute(unmanagedType) =
    inherit Attribute()
    
    // Define a property to get and set the UnmanagedType value.
    member val Win32Type = unmanagedType with get, set

// Create a module for an imported Win32 unmanaged function.
module Win32 =
    [<DllImport("user32.dll", CharSet = CharSet.Unicode)>]
    extern int MessageBox(IntPtr hWnd, String text, String caption, uint ``type``)

type AClass() =
    // Add some attributes to Win32CallMethod.
    [<Obsolete "This method is obsolete. Use managed MsgBox instead.">]
    [<Unmanaged(UnmanagedType.User)>]
    member _.Win32CallMethod () =
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0u)

// Get the AClass type to access its metadata.
let clsType = typeof<AClass>
// Get the type information for Win32CallMethod.
let mInfo = clsType.GetMethod "Win32CallMethod"
if mInfo <> null then
    // Iterate through all the attributes of the method.
    for attr in Attribute.GetCustomAttributes mInfo do
        match attr with 
        // Check for the Obsolete attribute.
        | :? ObsoleteAttribute as attr ->
            printfn $"Method {mInfo.Name} is obsolete. The message is:"
            printfn $"  \"{attr.Message}\""

        // Check for the Unmanaged attribute.
        | :? UnmanagedAttribute as attr ->
            printfn "This method calls unmanaged code."
            printfn $"The Unmanaged attribute type is {attr.Win32Type}."
            let myCls = AClass()
            myCls.Win32CallMethod() |> ignore
        | _ -> ()

// This code example produces the following results.
//
// First, the compilation yields the warning, "... This method is
// obsolete. Use managed MsgBox instead."
// Second, execution yields a message box with a title of "Caution!"
// and message text of "This is an unmanaged call."
// Third, the following text is displayed in the console window:

// Method Win32CallMethod is obsolete. The message is:
//   "This method is obsolete. Use managed MsgBox instead."
// This method calls unmanaged code.
// The Unmanaged attribute type is User.

Imports System.Reflection
Imports System.Security
Imports System.Runtime.InteropServices

' Define an enumeration of Win32 unmanaged types
Public Enum UnmanagedType
    User
    GDI
    Kernel
    Shell
    Networking
    Multimedia
End Enum 'UnmanagedType

' Define the Unmanaged attribute.
Public Class UnmanagedAttribute 
             Inherits Attribute

    ' Storage for the UnmanagedType value.
    Protected thisType As UnmanagedType
    
    ' Set the unmanaged type in the constructor.
    Public Sub New(ByVal type As UnmanagedType) 
        thisType = type
    End Sub
    
    ' Define a property to get and set the UnmanagedType value.
    Public Property Win32Type() As UnmanagedType 
        Get
            Return thisType
        End Get
        Set
            thisType = Win32Type
        End Set
    End Property
End Class

' Create a class for an imported Win32 unmanaged function.
Public Class Win32
    <DllImport("user32.dll", CharSet:=CharSet.Unicode)> _
    Public Shared Function MessageBox(ByVal hWnd As Integer, _
                                      ByVal Text As String, _
                                      ByVal caption As String, _
                                      ByVal type As Integer) As Integer
    End Function 'MessageBox
End Class

Public Class AClass
    ' Add some attributes to Win32CallMethod.
    <Obsolete("This method is obsolete. Use managed MsgBox instead."), _
     Unmanaged(UnmanagedType.User)>  _
    Public Sub Win32CallMethod() 
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0)    
    End Sub
End Class

Class DemoClass
    Shared Sub Main(ByVal args() As String) 
        ' Get the AClass type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for Win32CallMethod.
        Dim mInfo As MethodInfo = clsType.GetMethod("Win32CallMethod")
        If Not (mInfo Is Nothing) Then
            ' Iterate through all the attributes of the method.
            Dim attr As Attribute
            For Each attr In  Attribute.GetCustomAttributes(mInfo)
                ' Check for the Obsolete attribute.
                If attr.GetType().Equals(GetType(ObsoleteAttribute)) Then
                    Console.WriteLine("Method {0} is obsolete. The message is:", mInfo.Name)
                    Console.WriteLine("  ""{0}""", CType(attr, ObsoleteAttribute).Message)
                ' Check for the Unmanaged attribute.
                ElseIf attr.GetType().Equals(GetType(UnmanagedAttribute)) Then
                    Console.WriteLine("This method calls unmanaged code.")
                    Console.WriteLine( _
                            String.Format("The Unmanaged attribute type is {0}.", _
                            CType(attr, UnmanagedAttribute).Win32Type))
                    Dim myCls As New AClass()
                    myCls.Win32CallMethod()
                End If
            Next attr
        End If
    End Sub
End Class

'
'This code example produces the following results. 
'
'First, the compilation yields the warning, "... This method is 
'obsolete. Use managed MsgBox instead."
'Second, execution yields a message box with a title of "Caution!" 
'and message text of "This is an unmanaged call." 
'Third, the following text is displayed in the console window:
'
'Method Win32CallMethod is obsolete. The message is:
'  "This method is obsolete. Use managed MsgBox instead."
'This method calls unmanaged code.
'The Unmanaged attribute type is User.
'

注解

返回值包含上级属性的 element自定义属性。

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回方法、构造函数和类型的安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的 .NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Assembly, Type, Boolean)

检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集、要搜索的自定义属性的类型以及忽略的搜索选项。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Assembly ^ element, Type ^ attributeType, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.Assembly element, Type attributeType, bool inherit);

static member GetCustomAttributes : System.Reflection.Assembly * Type * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As Assembly, attributeType As Type, inherit As Boolean) As Attribute()

参数

element

Assembly

一个派生自 Assembly 类的对象，用于描述模块的可重用集合。

attributeType

Type

要搜索的自定义属性的类型或基类型。

inherit

Boolean

此参数被忽略，并且不会影响此方法的操作。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

示例

下面的代码示例演示了使用作为Assembly参数的用法GetCustomAttributes。

using namespace System;
using namespace System::Reflection;

[assembly:AssemblyTitle("CustAttrs1CPP")];
[assembly:AssemblyDescription("GetCustomAttributes() Demo")];
[assembly:AssemblyCompany("Microsoft")];

ref class Example
{};

static void main()
{
    Type^ clsType = Example::typeid;

    // Get the Assembly type to access its metadata.
    Assembly^ assy = clsType->Assembly;

    // Iterate through the attributes for the assembly.
    System::Collections::IEnumerator^ myEnum = Attribute::GetCustomAttributes( assy )->GetEnumerator();
    while ( myEnum->MoveNext() )
    {
       Attribute^ attr = safe_cast<Attribute^>(myEnum->Current);

       // Check for the AssemblyTitle attribute.
       if ( attr->GetType() == AssemblyTitleAttribute::typeid )
          Console::WriteLine( "Assembly title is \"{0}\".", (dynamic_cast<AssemblyTitleAttribute^>(attr))->Title );
          // Check for the AssemblyDescription attribute.
       else
          // Check for the AssemblyDescription attribute.
          if ( attr->GetType() == AssemblyDescriptionAttribute::typeid )
             Console::WriteLine( "Assembly description is \"{0}\".", (dynamic_cast<AssemblyDescriptionAttribute^>(attr))->Description );
          // Check for the AssemblyCompany attribute.
          else if ( attr->GetType() == AssemblyCompanyAttribute::typeid )
             Console::WriteLine( "Assembly company is {0}.", (dynamic_cast<AssemblyCompanyAttribute^>(attr))->Company );
    }
}
// The example displays the following output:
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.
//     Assembly title is "CustAttrs1CPP".

using System;
using System.Reflection;

[assembly: AssemblyTitle("CustAttrs1CS")]
[assembly: AssemblyDescription("GetCustomAttributes() Demo")]
[assembly: AssemblyCompany("Microsoft")]

class Example {
    static void Main() {
        // Get the Assembly object to access its metadata.
        Assembly assy = typeof(Example).Assembly;

        // Iterate through the attributes for the assembly.
        foreach(Attribute attr in Attribute.GetCustomAttributes(assy)) {
            // Check for the AssemblyTitle attribute.
            if (attr.GetType() == typeof(AssemblyTitleAttribute))
                Console.WriteLine("Assembly title is \"{0}\".",
                    ((AssemblyTitleAttribute)attr).Title);

            // Check for the AssemblyDescription attribute.
            else if (attr.GetType() ==
                typeof(AssemblyDescriptionAttribute))
                Console.WriteLine("Assembly description is \"{0}\".",
                    ((AssemblyDescriptionAttribute)attr).Description);

            // Check for the AssemblyCompany attribute.
            else if (attr.GetType() == typeof(AssemblyCompanyAttribute))
                Console.WriteLine("Assembly company is {0}.",
                    ((AssemblyCompanyAttribute)attr).Company);
        }
   }
}
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

open System
open System.Reflection

[<assembly: AssemblyTitle "CustAttrs1CS">]
[<assembly: AssemblyDescription "GetCustomAttributes() Demo">]
[<assembly: AssemblyCompany"Microsoft">]
do ()

type Example = class end

// Get the Assembly object to access its metadata.
let assembly = typeof<Example>.Assembly

// Iterate through the attributes for the assembly.
for attr in Attribute.GetCustomAttributes assembly do
    match attr with
    // Check for the AssemblyTitle attribute.
    | :? AssemblyTitleAttribute as attr ->    
        printfn $"Assembly title is \"{attr.Title}\"."
    // Check for the AssemblyDescription attribute.
    | :? AssemblyDescriptionAttribute as attr ->
        printfn $"Assembly description is \"{attr.Description}\"."
    // Check for the AssemblyCompany attribute.
    | :? AssemblyCompanyAttribute as attr ->
        printfn $"Assembly company is {attr.Company}."
    | _ -> ()
    
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

Imports System.Reflection

<Assembly: AssemblyTitle("CustAttrs1VB")> 
<Assembly: AssemblyDescription("GetCustomAttributes() Demo")> 
<Assembly: AssemblyCompany("Microsoft")> 

Module Example
    Sub Main()
        ' Get the Assembly type to access its metadata.
        Dim assy As Reflection.Assembly = GetType(Example).Assembly

        ' Iterate through all the attributes for the assembly.
        For Each attr As Attribute In Attribute.GetCustomAttributes(assy)
            ' Check for the AssemblyTitle attribute.
            If TypeOf attr Is AssemblyTitleAttribute Then
                ' Convert the attribute to access its data.
                Dim attrTitle As AssemblyTitleAttribute = _
                    CType(attr, AssemblyTitleAttribute)
                Console.WriteLine("Assembly title is ""{0}"".", _
                    attrTitle.Title)

            ' Check for the AssemblyDescription attribute.
            ElseIf TypeOf attr Is AssemblyDescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim attrDesc As AssemblyDescriptionAttribute = _
                    CType(attr, AssemblyDescriptionAttribute)
                Console.WriteLine("Assembly description is ""{0}"".", _
                    attrDesc.Description)

            ' Check for the AssemblyCompany attribute.
            ElseIf TypeOf attr Is AssemblyCompanyAttribute Then
                ' Convert the attribute to access its data.
                Dim attrComp As AssemblyCompanyAttribute = _
                    CType(attr, AssemblyCompanyAttribute)
                Console.WriteLine("Assembly company is {0}.", _
                    attrComp.Company)
            End If
        Next
    End Sub
End Module
' The example displays the following output:
'     Assembly company is Microsoft.
'     Assembly description is "GetCustomAttributes() Demo".
'     Assembly title is "CustAttrs1VB".

注解

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的 .NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Module, Type)

检索应用于模块的自定义属性的数组。 参数指定模块和要搜索的自定义属性的类型。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Module ^ element, Type ^ attributeType);

public static Attribute[] GetCustomAttributes (System.Reflection.Module element, Type attributeType);

static member GetCustomAttributes : System.Reflection.Module * Type -> Attribute[]

Public Shared Function GetCustomAttributes (element As Module, attributeType As Type) As Attribute()

参数

element

Module

一个从 Module 类派生的对象，该类描述可移植的可执行文件。

attributeType

Type

要搜索的自定义属性的类型或基类型。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesModule。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

// Assign some attributes to the module.
// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:Description("A sample description")];
[module:CLSCompliant(false)];
namespace CustAttrs2CS
{
   ref class DemoClass
   {
   public:
      static void Main()
      {
         Type^ clsType = DemoClass::typeid;

         // Get the Module type to access its metadata.
         Module^ module = clsType->Module;

         // Iterate through all the attributes for the module.
         System::Collections::IEnumerator^ myEnum1 = Attribute::GetCustomAttributes( module )->GetEnumerator();
         while ( myEnum1->MoveNext() )
         {
            Attribute^ attr = safe_cast<Attribute^>(myEnum1->Current);

            // Check for the Description attribute.
            if ( attr->GetType() == DescriptionAttribute::typeid )
                        Console::WriteLine( "Module {0} has the description \"{1}\".", module->Name, (dynamic_cast<DescriptionAttribute^>(attr))->Description );
            // Check for the CLSCompliant attribute.
            else

            // Check for the CLSCompliant attribute.
            if ( attr->GetType() == CLSCompliantAttribute::typeid )
                        Console::WriteLine( "Module {0} {1} CLSCompliant.", module->Name, (dynamic_cast<CLSCompliantAttribute^>(attr))->IsCompliant ? (String^)"is" : "is not" );
         }
      }
   };
}


/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

using System;
using System.Reflection;
using System.ComponentModel;

// Assign some attributes to the module.
[module:Description("A sample description")]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:CLSCompliant(false)]

namespace CustAttrs2CS {
    class DemoClass {
        static void Main(string[] args) {
            Type clsType = typeof(DemoClass);
            // Get the Module type to access its metadata.
            Module module = clsType.Module;

            // Iterate through all the attributes for the module.
            foreach(Attribute attr in Attribute.GetCustomAttributes(module)) {
                // Check for the Description attribute.
                if (attr.GetType() == typeof(DescriptionAttribute))
                    Console.WriteLine("Module {0} has the description " +
                        "\"{1}\".", module.Name,
                        ((DescriptionAttribute)attr).Description);
                // Check for the CLSCompliant attribute.
                else if (attr.GetType() == typeof(CLSCompliantAttribute))
                    Console.WriteLine("Module {0} {1} CLSCompliant.",
                        module.Name,
                        ((CLSCompliantAttribute)attr).IsCompliant ?
                            "is" : "is not");
            }
        }
    }
}

/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

open System
open System.ComponentModel

// Assign some attributes to the module.
[<``module``: Description "A sample description">]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[<``module``: CLSCompliant false>]
do ()

type DemoClass = class end

// Get the Module type to access its metadata.
let ilmodule = typeof<DemoClass>.Module

// Iterate through all the attributes for the module.
for attr in Attribute.GetCustomAttributes ilmodule do
    match attr with
    // Check for the Description attribute.
    | :? DescriptionAttribute as attr ->
        printfn $"Module {ilmodule.Name} has the description \"{attr.Description}\"."
                
    // Check for the CLSCompliant attribute.
    | :? CLSCompliantAttribute as attr ->
        printfn $"""Module {ilmodule.Name} {if attr.IsCompliant then "is" else "is not"} CLSCompliant."""
    | _ -> ()
    
// Output:
// Module CustAttrs2CS.exe is not CLSCompliant.
// Module CustAttrs2CS.exe has the description "A sample description".

Imports System.Reflection
Imports System.ComponentModel

' Give the Module some attributes.
<Module: Description("A sample description")> 

' Make the CLSCompliant attribute False.
' The CLSCompliant attribute is applicable for /target:module.
<Module: CLSCompliant(False)> 

Module DemoModule

    Sub Main()
        ' Get the Module type to access its metadata.
        Dim modType As Reflection.Module = GetType(DemoModule).Module
        Dim attr As Attribute
        ' Iterate through all the attributes for the module.
        For Each attr In Attribute.GetCustomAttributes(modType)
            ' Check for the Description attribute.
            If TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Module {0} has the description ""{1}"".", _
                    modType.Name, descAttr.Description)

            ' Check for the CLSCompliant attribute.
            ElseIf TypeOf attr Is CLSCompliantAttribute Then
                ' Convert the attribute to access its data.
                Dim CLSCompAttr As CLSCompliantAttribute = _
                    CType(attr, CLSCompliantAttribute)
                Dim strCompliant As String
                If CLSCompAttr.IsCompliant Then
                    strCompliant = "is"
                Else
                    strCompliant = "is not"
                End If
                Console.WriteLine("Module {0} {1} CLSCompliant.", _
                    modType.Name, strCompliant)
            End If
        Next
    End Sub
End Module

' Output:
' Module CustAttrs2VB.exe has the description "A sample description".
' Module CustAttrs2VB.exe is not CLSCompliant.

GetCustomAttributes(ParameterInfo, Type)

检索应用于方法参数的自定义属性的数组。 参数指定方法参数和要搜索的自定义属性的类型。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::ParameterInfo ^ element, Type ^ attributeType);

public static Attribute[] GetCustomAttributes (System.Reflection.ParameterInfo element, Type attributeType);

static member GetCustomAttributes : System.Reflection.ParameterInfo * Type -> Attribute[]

Public Shared Function GetCustomAttributes (element As ParameterInfo, attributeType As Type) As Attribute()

参数

element

ParameterInfo

一个从 ParameterInfo 类派生的对象，该类描述类成员的参数。

attributeType

Type

要搜索的自定义属性的类型或基类型。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesParameterInfo。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

namespace CustAttrs5CS
{
   public ref class AClass
   {
   public:
      void ParamArrayAndDesc(
         // Add ParamArray and Description attributes.
         [Description("This argument is a ParamArray")]
         array<Int32>^args )
      {}
   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the method.
         MethodInfo^ mInfo = clsType->GetMethod( "ParamArrayAndDesc" );
         if ( mInfo != nullptr )
         {
            // Get the parameter information.
            array<ParameterInfo^>^pInfo = mInfo->GetParameters();
            if ( pInfo != nullptr )
            {
               // Iterate through all the attributes for the parameter.
               System::Collections::IEnumerator^ myEnum4 = Attribute::GetCustomAttributes( pInfo[ 0 ] )->GetEnumerator();
               while ( myEnum4->MoveNext() )
               {
                  Attribute^ attr = safe_cast<Attribute^>(myEnum4->Current);

                  // Check for the ParamArray attribute.
                  if ( attr->GetType() == ParamArrayAttribute::typeid )
                                    Console::WriteLine( "Parameter {0} for method {1} "
                  "has the ParamArray attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                  // Check for the Description attribute.
                  else

                  // Check for the Description attribute.
                  if ( attr->GetType() == DescriptionAttribute::typeid )
                  {
                     Console::WriteLine( "Parameter {0} for method {1} "
                     "has a description attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                     Console::WriteLine( "The description is: \"{0}\"", (dynamic_cast<DescriptionAttribute^>(attr))->Description );
                  }
               }
            }
         }
      }
   };
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

using System;
using System.Reflection;
using System.ComponentModel;

namespace CustAttrs5CS {
    public class AClass {
        public void ParamArrayAndDesc(
            // Add ParamArray (with the keyword) and Description attributes.
            [Description("This argument is a ParamArray")]
            params int[] args)
        {}
    }

    class DemoClass {
        static void Main(string[] args) {
            // Get the Class type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for the method.
            MethodInfo mInfo = clsType.GetMethod("ParamArrayAndDesc");
            if (mInfo != null) {
                // Get the parameter information.
                ParameterInfo[] pInfo = mInfo.GetParameters();
                if (pInfo != null) {
                    // Iterate through all the attributes for the parameter.
                    foreach(Attribute attr in
                        Attribute.GetCustomAttributes(pInfo[0])) {
                        // Check for the ParamArray attribute.
                        if (attr.GetType() == typeof(ParamArrayAttribute))
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has the ParamArray attribute.",
                                pInfo[0].Name, mInfo.Name);
                        // Check for the Description attribute.
                        else if (attr.GetType() ==
                            typeof(DescriptionAttribute)) {
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has a description attribute.",
                                pInfo[0].Name, mInfo.Name);
                            Console.WriteLine("The description is: \"{0}\"",
                                ((DescriptionAttribute)attr).Description);
                        }
                    }
                }
            }
        }
    }
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

open System
open System.Reflection
open System.ComponentModel

type AClass() =
    member _.ParamArrayAndDesc(
        // Add ParamArray and Description attributes.
        [<Description "This argument is a ParamArray">]
        [<ParamArray>]
        args: int[]) = ()

// Get the Class type to access its metadata.
let clsType = typeof<AClass>

// Get the type information for the method.
let mInfo = clsType.GetMethod "ParamArrayAndDesc"
if mInfo <> null then
    // Get the parameter information.
    let pInfo = mInfo.GetParameters()
    if pInfo <> null then
        // Iterate through all the attributes for the parameter.
        for attr in Attribute.GetCustomAttributes pInfo[0] do
            match attr with 
            // Check for the ParamArray attribute.
            | :? ParamArrayAttribute ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has the ParamArray attribute."
                                
            // Check for the Description attribute.
            | :? DescriptionAttribute as attr ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has a description attribute."
                printfn $"The description is: \"{attr.Description}\""
            | _ -> ()

// Output:
// Parameter args for method ParamArrayAndDesc has a description attribute.
// The description is: "This argument is a ParamArray"
// Parameter args for method ParamArrayAndDesc has the ParamArray attribute.

Imports System.Reflection
Imports System.ComponentModel

Module DemoModule
    Public Class AClass
        ' Add Description and ParamArray (with the keyword) attributes.
        Public Sub ParamArrayAndDesc( _
            <Description("This argument is a ParamArray")> _
            ByVal ParamArray args() As Integer)
        End Sub
    End Class

    Sub Main()
        ' Get the Class type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for the method.
        Dim mInfo As MethodInfo = clsType.GetMethod("ParamArrayAndDesc")
        ' Get the Parameter information for the method.
        Dim pInfo() As ParameterInfo = mInfo.GetParameters()
        Dim attr As Attribute
        ' Iterate through each attribute of the parameter.
        For Each attr In Attribute.GetCustomAttributes(pInfo(0))
            ' Check for the ParamArray attribute.
            If TypeOf attr Is ParamArrayAttribute Then
                ' Convert the attribute to access its data.
                Dim paAttr As ParamArrayAttribute = _
                    CType(attr, ParamArrayAttribute)
                Console.WriteLine("Parameter {0} for method {1} has the " + _
                    "ParamArray attribute.", pInfo(0).Name, mInfo.Name)
            ' Check for the Description attribute.
            ElseIf TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Parameter {0} for method {1} has a description " + _
                    "attribute. The description is:", pInfo(0).Name, mInfo.Name)
                Console.WriteLine(descAttr.Description)
            End If
        Next
    End Sub
End Module

' Output:
' Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
' Parameter args for method ParamArrayAndDesc has a description attribute. The description is:
' This argument is a ParamArray

注解

如果 element 表示派生类型的方法中的参数，则返回值包括应用于重写基方法中同一参数的可继承自定义属性。

GetCustomAttributes(MemberInfo, Boolean)

检索应用于类型的成员的自定义属性的数组。 参数指定成员、要搜索的自定义属性的类型以及是否搜索成员的祖先。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element, bool inherit);

static member GetCustomAttributes : System.Reflection.MemberInfo * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As MemberInfo, inherit As Boolean) As Attribute()

参数

element

MemberInfo

一个从 MemberInfo 类派生的对象，该类描述类的构造函数、事件、字段、方法或属性成员。

inherit

Boolean

如果为 true，则指定还在 element 的祖先中搜索自定义属性。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 为 null。

NotSupportedException

element 不是构造函数、方法、属性、事件、类型或字段。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesMemberInfo。

using namespace System;
using namespace System::Reflection;
using namespace System::Security;
using namespace System::Runtime::InteropServices;

namespace CustAttrs4CS
{
   // Create a class for Win32 imported unmanaged functions.
   public ref class Win32
   {
   public:

      [DllImport("user32.dll", CharSet = CharSet::Unicode)]
      static int MessageBox( int hWnd, String^ text, String^ caption, UInt32 type );
   };

   public ref class AClass
   {
   public:

      // Add some attributes to the Win32CallMethod.

      [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
      void Win32CallMethod()
      {
         Win32::MessageBox( 0, "This is an unmanaged call.", "Be Careful!", 0 );
      }

   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the Win32CallMethod.
         MethodInfo^ mInfo = clsType->GetMethod( "Win32CallMethod" );
         if ( mInfo != nullptr )
         {
            // Iterate through all the attributes for the method.
            System::Collections::IEnumerator^ myEnum3 = Attribute::GetCustomAttributes( mInfo )->GetEnumerator();
            while ( myEnum3->MoveNext() )
            {
               Attribute^ attr = safe_cast<Attribute^>(myEnum3->Current);

               // Check for the Obsolete attribute.
               if ( attr->GetType() == ObsoleteAttribute::typeid )
               {
                  Console::WriteLine( "Method {0} is obsolete. "
                  "The message is:", mInfo->Name );
                  Console::WriteLine( (dynamic_cast<ObsoleteAttribute^>(attr))->Message );
               }
               // Check for the SuppressUnmanagedCodeSecurity attribute.
               else

               // Check for the SuppressUnmanagedCodeSecurity attribute.
               if ( attr->GetType() == SuppressUnmanagedCodeSecurityAttribute::typeid )
               {
                  Console::WriteLine( "This method calls unmanaged code "
                  "with no security check." );
                  Console::WriteLine( "Please do not use unless absolutely necessary." );
                  AClass^ myCls = gcnew AClass;
                  myCls->Win32CallMethod();
               }
            }
         }
      }
   };
}


/*
 * Output:
 * Method Win32CallMethod is obsolete. The message is:
 * This method is obsolete. Use managed MsgBox instead.
 * This method calls unmanaged code with no security check.
 * Please do not use unless absolutely necessary.
 */

using System;
using System.Reflection;
using System.Security;
using System.Runtime.InteropServices;

namespace CustAttrs4CS
{

    // Define an enumeration of Win32 unmanaged types
    public enum UnmanagedType
    {
        User,
        GDI,
        Kernel,
        Shell,
        Networking,
        Multimedia
    }

    // Define the Unmanaged attribute.
    public class UnmanagedAttribute : Attribute
    {
        // Storage for the UnmanagedType value.
        protected UnmanagedType thisType;

        // Set the unmanaged type in the constructor.
        public UnmanagedAttribute(UnmanagedType type)
        {
            thisType = type;
        }

        // Define a property to get and set the UnmanagedType value.
        public UnmanagedType Win32Type
        {
            get { return thisType; }
            set { thisType = Win32Type; }
        }
    }

    // Create a class for an imported Win32 unmanaged function.
    public class Win32 {
        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        public static extern int MessageBox(int hWnd, String text,
            String caption, uint type);
    }

    public class AClass {
        // Add some attributes to Win32CallMethod.
        [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
        [Unmanaged(UnmanagedType.User)]
        public void Win32CallMethod()
        {
            Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0);
        }
    }

    class DemoClass {
        static void Main(string[] args)
            {
            // Get the AClass type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for Win32CallMethod.
            MethodInfo mInfo = clsType.GetMethod("Win32CallMethod");
            if (mInfo != null)
            {
                // Iterate through all the attributes of the method.
                foreach(Attribute attr in
                    Attribute.GetCustomAttributes(mInfo)) {
                    // Check for the Obsolete attribute.
                    if (attr.GetType() == typeof(ObsoleteAttribute))
                    {
                        Console.WriteLine("Method {0} is obsolete. " +
                            "The message is:",
                            mInfo.Name);
                        Console.WriteLine("  \"{0}\"",
                            ((ObsoleteAttribute)attr).Message);
                    }

                    // Check for the Unmanaged attribute.
                    else if (attr.GetType() == typeof(UnmanagedAttribute))
                    {
                        Console.WriteLine(
                            "This method calls unmanaged code.");
                        Console.WriteLine(
                            String.Format("The Unmanaged attribute type is {0}.",
                                          ((UnmanagedAttribute)attr).Win32Type));
                        AClass myCls = new AClass();
                        myCls.Win32CallMethod();
                    }
                }
            }
        }
    }
}

/*

This code example produces the following results.

First, the compilation yields the warning, "... This method is
obsolete. Use managed MsgBox instead."
Second, execution yields a message box with a title of "Caution!"
and message text of "This is an unmanaged call."
Third, the following text is displayed in the console window:

Method Win32CallMethod is obsolete. The message is:
  "This method is obsolete. Use managed MsgBox instead."
This method calls unmanaged code.
The Unmanaged attribute type is User.

*/

open System
open System.Runtime.InteropServices

// Define an enumeration of Win32 unmanaged types
type UnmanagedType =
    | User = 0
    | GDI = 1
    | Kernel = 2
    | Shell = 3
    | Networking = 4
    | Multimedia = 5

// Define the Unmanaged attribute.
type UnmanagedAttribute(unmanagedType) =
    inherit Attribute()
    
    // Define a property to get and set the UnmanagedType value.
    member val Win32Type = unmanagedType with get, set

// Create a module for an imported Win32 unmanaged function.
module Win32 =
    [<DllImport("user32.dll", CharSet = CharSet.Unicode)>]
    extern int MessageBox(IntPtr hWnd, String text, String caption, uint ``type``)

type AClass() =
    // Add some attributes to Win32CallMethod.
    [<Obsolete "This method is obsolete. Use managed MsgBox instead.">]
    [<Unmanaged(UnmanagedType.User)>]
    member _.Win32CallMethod () =
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0u)

// Get the AClass type to access its metadata.
let clsType = typeof<AClass>
// Get the type information for Win32CallMethod.
let mInfo = clsType.GetMethod "Win32CallMethod"
if mInfo <> null then
    // Iterate through all the attributes of the method.
    for attr in Attribute.GetCustomAttributes mInfo do
        match attr with 
        // Check for the Obsolete attribute.
        | :? ObsoleteAttribute as attr ->
            printfn $"Method {mInfo.Name} is obsolete. The message is:"
            printfn $"  \"{attr.Message}\""

        // Check for the Unmanaged attribute.
        | :? UnmanagedAttribute as attr ->
            printfn "This method calls unmanaged code."
            printfn $"The Unmanaged attribute type is {attr.Win32Type}."
            let myCls = AClass()
            myCls.Win32CallMethod() |> ignore
        | _ -> ()

// This code example produces the following results.
//
// First, the compilation yields the warning, "... This method is
// obsolete. Use managed MsgBox instead."
// Second, execution yields a message box with a title of "Caution!"
// and message text of "This is an unmanaged call."
// Third, the following text is displayed in the console window:

// Method Win32CallMethod is obsolete. The message is:
//   "This method is obsolete. Use managed MsgBox instead."
// This method calls unmanaged code.
// The Unmanaged attribute type is User.

Imports System.Reflection
Imports System.Security
Imports System.Runtime.InteropServices

' Define an enumeration of Win32 unmanaged types
Public Enum UnmanagedType
    User
    GDI
    Kernel
    Shell
    Networking
    Multimedia
End Enum 'UnmanagedType

' Define the Unmanaged attribute.
Public Class UnmanagedAttribute 
             Inherits Attribute

    ' Storage for the UnmanagedType value.
    Protected thisType As UnmanagedType
    
    ' Set the unmanaged type in the constructor.
    Public Sub New(ByVal type As UnmanagedType) 
        thisType = type
    End Sub
    
    ' Define a property to get and set the UnmanagedType value.
    Public Property Win32Type() As UnmanagedType 
        Get
            Return thisType
        End Get
        Set
            thisType = Win32Type
        End Set
    End Property
End Class

' Create a class for an imported Win32 unmanaged function.
Public Class Win32
    <DllImport("user32.dll", CharSet:=CharSet.Unicode)> _
    Public Shared Function MessageBox(ByVal hWnd As Integer, _
                                      ByVal Text As String, _
                                      ByVal caption As String, _
                                      ByVal type As Integer) As Integer
    End Function 'MessageBox
End Class

Public Class AClass
    ' Add some attributes to Win32CallMethod.
    <Obsolete("This method is obsolete. Use managed MsgBox instead."), _
     Unmanaged(UnmanagedType.User)>  _
    Public Sub Win32CallMethod() 
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0)    
    End Sub
End Class

Class DemoClass
    Shared Sub Main(ByVal args() As String) 
        ' Get the AClass type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for Win32CallMethod.
        Dim mInfo As MethodInfo = clsType.GetMethod("Win32CallMethod")
        If Not (mInfo Is Nothing) Then
            ' Iterate through all the attributes of the method.
            Dim attr As Attribute
            For Each attr In  Attribute.GetCustomAttributes(mInfo)
                ' Check for the Obsolete attribute.
                If attr.GetType().Equals(GetType(ObsoleteAttribute)) Then
                    Console.WriteLine("Method {0} is obsolete. The message is:", mInfo.Name)
                    Console.WriteLine("  ""{0}""", CType(attr, ObsoleteAttribute).Message)
                ' Check for the Unmanaged attribute.
                ElseIf attr.GetType().Equals(GetType(UnmanagedAttribute)) Then
                    Console.WriteLine("This method calls unmanaged code.")
                    Console.WriteLine( _
                            String.Format("The Unmanaged attribute type is {0}.", _
                            CType(attr, UnmanagedAttribute).Win32Type))
                    Dim myCls As New AClass()
                    myCls.Win32CallMethod()
                End If
            Next attr
        End If
    End Sub
End Class

'
'This code example produces the following results. 
'
'First, the compilation yields the warning, "... This method is 
'obsolete. Use managed MsgBox instead."
'Second, execution yields a message box with a title of "Caution!" 
'and message text of "This is an unmanaged call." 
'Third, the following text is displayed in the console window:
'
'Method Win32CallMethod is obsolete. The message is:
'  "This method is obsolete. Use managed MsgBox instead."
'This method calls unmanaged code.
'The Unmanaged attribute type is User.
'

注解

返回值包含上级 element 为 if inherit 的 true自定义属性。

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回方法、构造函数和类型的安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的 .NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Assembly, Type)

检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集和要搜索的自定义属性的类型。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Assembly ^ element, Type ^ attributeType);

public static Attribute[] GetCustomAttributes (System.Reflection.Assembly element, Type attributeType);

static member GetCustomAttributes : System.Reflection.Assembly * Type -> Attribute[]

Public Shared Function GetCustomAttributes (element As Assembly, attributeType As Type) As Attribute()

参数

element

Assembly

一个派生自 Assembly 类的对象，用于描述模块的可重用集合。

attributeType

Type

要搜索的自定义属性的类型或基类型。

返回

Attribute[]

一个 Attribute 数组，包含应用于 attributeType 的 element 类型的自定义属性；如果不存在此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

ArgumentException

attributeType 不是从 Attribute 派生的。

示例

下面的代码示例演示了如何使用 GetCustomAttributes作为 Assembly 参数。

using namespace System;
using namespace System::Reflection;

[assembly:AssemblyTitle("CustAttrs1CPP")];
[assembly:AssemblyDescription("GetCustomAttributes() Demo")];
[assembly:AssemblyCompany("Microsoft")];

ref class Example
{};

static void main()
{
    Type^ clsType = Example::typeid;

    // Get the Assembly type to access its metadata.
    Assembly^ assy = clsType->Assembly;

    // Iterate through the attributes for the assembly.
    System::Collections::IEnumerator^ myEnum = Attribute::GetCustomAttributes( assy )->GetEnumerator();
    while ( myEnum->MoveNext() )
    {
       Attribute^ attr = safe_cast<Attribute^>(myEnum->Current);

       // Check for the AssemblyTitle attribute.
       if ( attr->GetType() == AssemblyTitleAttribute::typeid )
          Console::WriteLine( "Assembly title is \"{0}\".", (dynamic_cast<AssemblyTitleAttribute^>(attr))->Title );
          // Check for the AssemblyDescription attribute.
       else
          // Check for the AssemblyDescription attribute.
          if ( attr->GetType() == AssemblyDescriptionAttribute::typeid )
             Console::WriteLine( "Assembly description is \"{0}\".", (dynamic_cast<AssemblyDescriptionAttribute^>(attr))->Description );
          // Check for the AssemblyCompany attribute.
          else if ( attr->GetType() == AssemblyCompanyAttribute::typeid )
             Console::WriteLine( "Assembly company is {0}.", (dynamic_cast<AssemblyCompanyAttribute^>(attr))->Company );
    }
}
// The example displays the following output:
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.
//     Assembly title is "CustAttrs1CPP".

using System;
using System.Reflection;

[assembly: AssemblyTitle("CustAttrs1CS")]
[assembly: AssemblyDescription("GetCustomAttributes() Demo")]
[assembly: AssemblyCompany("Microsoft")]

class Example {
    static void Main() {
        // Get the Assembly object to access its metadata.
        Assembly assy = typeof(Example).Assembly;

        // Iterate through the attributes for the assembly.
        foreach(Attribute attr in Attribute.GetCustomAttributes(assy)) {
            // Check for the AssemblyTitle attribute.
            if (attr.GetType() == typeof(AssemblyTitleAttribute))
                Console.WriteLine("Assembly title is \"{0}\".",
                    ((AssemblyTitleAttribute)attr).Title);

            // Check for the AssemblyDescription attribute.
            else if (attr.GetType() ==
                typeof(AssemblyDescriptionAttribute))
                Console.WriteLine("Assembly description is \"{0}\".",
                    ((AssemblyDescriptionAttribute)attr).Description);

            // Check for the AssemblyCompany attribute.
            else if (attr.GetType() == typeof(AssemblyCompanyAttribute))
                Console.WriteLine("Assembly company is {0}.",
                    ((AssemblyCompanyAttribute)attr).Company);
        }
   }
}
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

open System
open System.Reflection

[<assembly: AssemblyTitle "CustAttrs1CS">]
[<assembly: AssemblyDescription "GetCustomAttributes() Demo">]
[<assembly: AssemblyCompany"Microsoft">]
do ()

type Example = class end

// Get the Assembly object to access its metadata.
let assembly = typeof<Example>.Assembly

// Iterate through the attributes for the assembly.
for attr in Attribute.GetCustomAttributes assembly do
    match attr with
    // Check for the AssemblyTitle attribute.
    | :? AssemblyTitleAttribute as attr ->    
        printfn $"Assembly title is \"{attr.Title}\"."
    // Check for the AssemblyDescription attribute.
    | :? AssemblyDescriptionAttribute as attr ->
        printfn $"Assembly description is \"{attr.Description}\"."
    // Check for the AssemblyCompany attribute.
    | :? AssemblyCompanyAttribute as attr ->
        printfn $"Assembly company is {attr.Company}."
    | _ -> ()
    
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

Imports System.Reflection

<Assembly: AssemblyTitle("CustAttrs1VB")> 
<Assembly: AssemblyDescription("GetCustomAttributes() Demo")> 
<Assembly: AssemblyCompany("Microsoft")> 

Module Example
    Sub Main()
        ' Get the Assembly type to access its metadata.
        Dim assy As Reflection.Assembly = GetType(Example).Assembly

        ' Iterate through all the attributes for the assembly.
        For Each attr As Attribute In Attribute.GetCustomAttributes(assy)
            ' Check for the AssemblyTitle attribute.
            If TypeOf attr Is AssemblyTitleAttribute Then
                ' Convert the attribute to access its data.
                Dim attrTitle As AssemblyTitleAttribute = _
                    CType(attr, AssemblyTitleAttribute)
                Console.WriteLine("Assembly title is ""{0}"".", _
                    attrTitle.Title)

            ' Check for the AssemblyDescription attribute.
            ElseIf TypeOf attr Is AssemblyDescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim attrDesc As AssemblyDescriptionAttribute = _
                    CType(attr, AssemblyDescriptionAttribute)
                Console.WriteLine("Assembly description is ""{0}"".", _
                    attrDesc.Description)

            ' Check for the AssemblyCompany attribute.
            ElseIf TypeOf attr Is AssemblyCompanyAttribute Then
                ' Convert the attribute to access its data.
                Dim attrComp As AssemblyCompanyAttribute = _
                    CType(attr, AssemblyCompanyAttribute)
                Console.WriteLine("Assembly company is {0}.", _
                    attrComp.Company)
            End If
        Next
    End Sub
End Module
' The example displays the following output:
'     Assembly company is Microsoft.
'     Assembly description is "GetCustomAttributes() Demo".
'     Assembly title is "CustAttrs1VB".

注解

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的.NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Assembly, Boolean)

检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集及忽略的搜索选项。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Assembly ^ element, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.Assembly element, bool inherit);

static member GetCustomAttributes : System.Reflection.Assembly * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As Assembly, inherit As Boolean) As Attribute()

参数

element

Assembly

一个派生自 Assembly 类的对象，用于描述模块的可重用集合。

inherit

Boolean

此参数被忽略，并且不会影响此方法的操作。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

示例

下面的代码示例演示了如何使用 GetCustomAttributes作为 Assembly 参数。

using namespace System;
using namespace System::Reflection;

[assembly:AssemblyTitle("CustAttrs1CPP")];
[assembly:AssemblyDescription("GetCustomAttributes() Demo")];
[assembly:AssemblyCompany("Microsoft")];

ref class Example
{};

static void main()
{
    Type^ clsType = Example::typeid;

    // Get the Assembly type to access its metadata.
    Assembly^ assy = clsType->Assembly;

    // Iterate through the attributes for the assembly.
    System::Collections::IEnumerator^ myEnum = Attribute::GetCustomAttributes( assy )->GetEnumerator();
    while ( myEnum->MoveNext() )
    {
       Attribute^ attr = safe_cast<Attribute^>(myEnum->Current);

       // Check for the AssemblyTitle attribute.
       if ( attr->GetType() == AssemblyTitleAttribute::typeid )
          Console::WriteLine( "Assembly title is \"{0}\".", (dynamic_cast<AssemblyTitleAttribute^>(attr))->Title );
          // Check for the AssemblyDescription attribute.
       else
          // Check for the AssemblyDescription attribute.
          if ( attr->GetType() == AssemblyDescriptionAttribute::typeid )
             Console::WriteLine( "Assembly description is \"{0}\".", (dynamic_cast<AssemblyDescriptionAttribute^>(attr))->Description );
          // Check for the AssemblyCompany attribute.
          else if ( attr->GetType() == AssemblyCompanyAttribute::typeid )
             Console::WriteLine( "Assembly company is {0}.", (dynamic_cast<AssemblyCompanyAttribute^>(attr))->Company );
    }
}
// The example displays the following output:
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.
//     Assembly title is "CustAttrs1CPP".

using System;
using System.Reflection;

[assembly: AssemblyTitle("CustAttrs1CS")]
[assembly: AssemblyDescription("GetCustomAttributes() Demo")]
[assembly: AssemblyCompany("Microsoft")]

class Example {
    static void Main() {
        // Get the Assembly object to access its metadata.
        Assembly assy = typeof(Example).Assembly;

        // Iterate through the attributes for the assembly.
        foreach(Attribute attr in Attribute.GetCustomAttributes(assy)) {
            // Check for the AssemblyTitle attribute.
            if (attr.GetType() == typeof(AssemblyTitleAttribute))
                Console.WriteLine("Assembly title is \"{0}\".",
                    ((AssemblyTitleAttribute)attr).Title);

            // Check for the AssemblyDescription attribute.
            else if (attr.GetType() ==
                typeof(AssemblyDescriptionAttribute))
                Console.WriteLine("Assembly description is \"{0}\".",
                    ((AssemblyDescriptionAttribute)attr).Description);

            // Check for the AssemblyCompany attribute.
            else if (attr.GetType() == typeof(AssemblyCompanyAttribute))
                Console.WriteLine("Assembly company is {0}.",
                    ((AssemblyCompanyAttribute)attr).Company);
        }
   }
}
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

open System
open System.Reflection

[<assembly: AssemblyTitle "CustAttrs1CS">]
[<assembly: AssemblyDescription "GetCustomAttributes() Demo">]
[<assembly: AssemblyCompany"Microsoft">]
do ()

type Example = class end

// Get the Assembly object to access its metadata.
let assembly = typeof<Example>.Assembly

// Iterate through the attributes for the assembly.
for attr in Attribute.GetCustomAttributes assembly do
    match attr with
    // Check for the AssemblyTitle attribute.
    | :? AssemblyTitleAttribute as attr ->    
        printfn $"Assembly title is \"{attr.Title}\"."
    // Check for the AssemblyDescription attribute.
    | :? AssemblyDescriptionAttribute as attr ->
        printfn $"Assembly description is \"{attr.Description}\"."
    // Check for the AssemblyCompany attribute.
    | :? AssemblyCompanyAttribute as attr ->
        printfn $"Assembly company is {attr.Company}."
    | _ -> ()
    
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

Imports System.Reflection

<Assembly: AssemblyTitle("CustAttrs1VB")> 
<Assembly: AssemblyDescription("GetCustomAttributes() Demo")> 
<Assembly: AssemblyCompany("Microsoft")> 

Module Example
    Sub Main()
        ' Get the Assembly type to access its metadata.
        Dim assy As Reflection.Assembly = GetType(Example).Assembly

        ' Iterate through all the attributes for the assembly.
        For Each attr As Attribute In Attribute.GetCustomAttributes(assy)
            ' Check for the AssemblyTitle attribute.
            If TypeOf attr Is AssemblyTitleAttribute Then
                ' Convert the attribute to access its data.
                Dim attrTitle As AssemblyTitleAttribute = _
                    CType(attr, AssemblyTitleAttribute)
                Console.WriteLine("Assembly title is ""{0}"".", _
                    attrTitle.Title)

            ' Check for the AssemblyDescription attribute.
            ElseIf TypeOf attr Is AssemblyDescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim attrDesc As AssemblyDescriptionAttribute = _
                    CType(attr, AssemblyDescriptionAttribute)
                Console.WriteLine("Assembly description is ""{0}"".", _
                    attrDesc.Description)

            ' Check for the AssemblyCompany attribute.
            ElseIf TypeOf attr Is AssemblyCompanyAttribute Then
                ' Convert the attribute to access its data.
                Dim attrComp As AssemblyCompanyAttribute = _
                    CType(attr, AssemblyCompanyAttribute)
                Console.WriteLine("Assembly company is {0}.", _
                    attrComp.Company)
            End If
        Next
    End Sub
End Module
' The example displays the following output:
'     Assembly company is Microsoft.
'     Assembly description is "GetCustomAttributes() Demo".
'     Assembly title is "CustAttrs1VB".

注解

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的.NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(ParameterInfo)

检索应用于方法参数的自定义属性的数组。 参数指定方法参数。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::ParameterInfo ^ element);

public static Attribute[] GetCustomAttributes (System.Reflection.ParameterInfo element);

static member GetCustomAttributes : System.Reflection.ParameterInfo -> Attribute[]

Public Shared Function GetCustomAttributes (element As ParameterInfo) As Attribute()

参数

element

ParameterInfo

一个从 ParameterInfo 类派生的对象，该类描述类成员的参数。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 为 null。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了如何使用 GetCustomAttributes作为 ParameterInfo 参数。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

namespace CustAttrs5CS
{
   public ref class AClass
   {
   public:
      void ParamArrayAndDesc(
         // Add ParamArray and Description attributes.
         [Description("This argument is a ParamArray")]
         array<Int32>^args )
      {}
   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the method.
         MethodInfo^ mInfo = clsType->GetMethod( "ParamArrayAndDesc" );
         if ( mInfo != nullptr )
         {
            // Get the parameter information.
            array<ParameterInfo^>^pInfo = mInfo->GetParameters();
            if ( pInfo != nullptr )
            {
               // Iterate through all the attributes for the parameter.
               System::Collections::IEnumerator^ myEnum4 = Attribute::GetCustomAttributes( pInfo[ 0 ] )->GetEnumerator();
               while ( myEnum4->MoveNext() )
               {
                  Attribute^ attr = safe_cast<Attribute^>(myEnum4->Current);

                  // Check for the ParamArray attribute.
                  if ( attr->GetType() == ParamArrayAttribute::typeid )
                                    Console::WriteLine( "Parameter {0} for method {1} "
                  "has the ParamArray attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                  // Check for the Description attribute.
                  else

                  // Check for the Description attribute.
                  if ( attr->GetType() == DescriptionAttribute::typeid )
                  {
                     Console::WriteLine( "Parameter {0} for method {1} "
                     "has a description attribute.", pInfo[ 0 ]->Name, mInfo->Name );
                     Console::WriteLine( "The description is: \"{0}\"", (dynamic_cast<DescriptionAttribute^>(attr))->Description );
                  }
               }
            }
         }
      }
   };
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

using System;
using System.Reflection;
using System.ComponentModel;

namespace CustAttrs5CS {
    public class AClass {
        public void ParamArrayAndDesc(
            // Add ParamArray (with the keyword) and Description attributes.
            [Description("This argument is a ParamArray")]
            params int[] args)
        {}
    }

    class DemoClass {
        static void Main(string[] args) {
            // Get the Class type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for the method.
            MethodInfo mInfo = clsType.GetMethod("ParamArrayAndDesc");
            if (mInfo != null) {
                // Get the parameter information.
                ParameterInfo[] pInfo = mInfo.GetParameters();
                if (pInfo != null) {
                    // Iterate through all the attributes for the parameter.
                    foreach(Attribute attr in
                        Attribute.GetCustomAttributes(pInfo[0])) {
                        // Check for the ParamArray attribute.
                        if (attr.GetType() == typeof(ParamArrayAttribute))
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has the ParamArray attribute.",
                                pInfo[0].Name, mInfo.Name);
                        // Check for the Description attribute.
                        else if (attr.GetType() ==
                            typeof(DescriptionAttribute)) {
                            Console.WriteLine("Parameter {0} for method {1} " +
                                "has a description attribute.",
                                pInfo[0].Name, mInfo.Name);
                            Console.WriteLine("The description is: \"{0}\"",
                                ((DescriptionAttribute)attr).Description);
                        }
                    }
                }
            }
        }
    }
}

/*
 * Output:
 * Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
 * Parameter args for method ParamArrayAndDesc has a description attribute.
 * The description is: "This argument is a ParamArray"
 */

open System
open System.Reflection
open System.ComponentModel

type AClass() =
    member _.ParamArrayAndDesc(
        // Add ParamArray and Description attributes.
        [<Description "This argument is a ParamArray">]
        [<ParamArray>]
        args: int[]) = ()

// Get the Class type to access its metadata.
let clsType = typeof<AClass>

// Get the type information for the method.
let mInfo = clsType.GetMethod "ParamArrayAndDesc"
if mInfo <> null then
    // Get the parameter information.
    let pInfo = mInfo.GetParameters()
    if pInfo <> null then
        // Iterate through all the attributes for the parameter.
        for attr in Attribute.GetCustomAttributes pInfo[0] do
            match attr with 
            // Check for the ParamArray attribute.
            | :? ParamArrayAttribute ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has the ParamArray attribute."
                                
            // Check for the Description attribute.
            | :? DescriptionAttribute as attr ->
                printfn $"Parameter {pInfo[0].Name} for method {mInfo.Name} has a description attribute."
                printfn $"The description is: \"{attr.Description}\""
            | _ -> ()

// Output:
// Parameter args for method ParamArrayAndDesc has a description attribute.
// The description is: "This argument is a ParamArray"
// Parameter args for method ParamArrayAndDesc has the ParamArray attribute.

Imports System.Reflection
Imports System.ComponentModel

Module DemoModule
    Public Class AClass
        ' Add Description and ParamArray (with the keyword) attributes.
        Public Sub ParamArrayAndDesc( _
            <Description("This argument is a ParamArray")> _
            ByVal ParamArray args() As Integer)
        End Sub
    End Class

    Sub Main()
        ' Get the Class type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for the method.
        Dim mInfo As MethodInfo = clsType.GetMethod("ParamArrayAndDesc")
        ' Get the Parameter information for the method.
        Dim pInfo() As ParameterInfo = mInfo.GetParameters()
        Dim attr As Attribute
        ' Iterate through each attribute of the parameter.
        For Each attr In Attribute.GetCustomAttributes(pInfo(0))
            ' Check for the ParamArray attribute.
            If TypeOf attr Is ParamArrayAttribute Then
                ' Convert the attribute to access its data.
                Dim paAttr As ParamArrayAttribute = _
                    CType(attr, ParamArrayAttribute)
                Console.WriteLine("Parameter {0} for method {1} has the " + _
                    "ParamArray attribute.", pInfo(0).Name, mInfo.Name)
            ' Check for the Description attribute.
            ElseIf TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Parameter {0} for method {1} has a description " + _
                    "attribute. The description is:", pInfo(0).Name, mInfo.Name)
                Console.WriteLine(descAttr.Description)
            End If
        Next
    End Sub
End Module

' Output:
' Parameter args for method ParamArrayAndDesc has the ParamArray attribute.
' Parameter args for method ParamArrayAndDesc has a description attribute. The description is:
' This argument is a ParamArray

注解

如果 element 表示派生类型的方法中的参数，则返回值包括应用于重写基方法中相同参数的可继承自定义属性。

GetCustomAttributes(Module)

检索应用于模块的自定义属性的数组。 参数指定模块。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Module ^ element);

public static Attribute[] GetCustomAttributes (System.Reflection.Module element);

static member GetCustomAttributes : System.Reflection.Module -> Attribute[]

Public Shared Function GetCustomAttributes (element As Module) As Attribute()

参数

element

Module

一个从 Module 类派生的对象，该类描述可移植的可执行文件。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 为 null。

示例

下面的代码示例演示了如何使用 GetCustomAttributes作为 Module 参数。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

// Assign some attributes to the module.
// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:Description("A sample description")];
[module:CLSCompliant(false)];
namespace CustAttrs2CS
{
   ref class DemoClass
   {
   public:
      static void Main()
      {
         Type^ clsType = DemoClass::typeid;

         // Get the Module type to access its metadata.
         Module^ module = clsType->Module;

         // Iterate through all the attributes for the module.
         System::Collections::IEnumerator^ myEnum1 = Attribute::GetCustomAttributes( module )->GetEnumerator();
         while ( myEnum1->MoveNext() )
         {
            Attribute^ attr = safe_cast<Attribute^>(myEnum1->Current);

            // Check for the Description attribute.
            if ( attr->GetType() == DescriptionAttribute::typeid )
                        Console::WriteLine( "Module {0} has the description \"{1}\".", module->Name, (dynamic_cast<DescriptionAttribute^>(attr))->Description );
            // Check for the CLSCompliant attribute.
            else

            // Check for the CLSCompliant attribute.
            if ( attr->GetType() == CLSCompliantAttribute::typeid )
                        Console::WriteLine( "Module {0} {1} CLSCompliant.", module->Name, (dynamic_cast<CLSCompliantAttribute^>(attr))->IsCompliant ? (String^)"is" : "is not" );
         }
      }
   };
}


/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

using System;
using System.Reflection;
using System.ComponentModel;

// Assign some attributes to the module.
[module:Description("A sample description")]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:CLSCompliant(false)]

namespace CustAttrs2CS {
    class DemoClass {
        static void Main(string[] args) {
            Type clsType = typeof(DemoClass);
            // Get the Module type to access its metadata.
            Module module = clsType.Module;

            // Iterate through all the attributes for the module.
            foreach(Attribute attr in Attribute.GetCustomAttributes(module)) {
                // Check for the Description attribute.
                if (attr.GetType() == typeof(DescriptionAttribute))
                    Console.WriteLine("Module {0} has the description " +
                        "\"{1}\".", module.Name,
                        ((DescriptionAttribute)attr).Description);
                // Check for the CLSCompliant attribute.
                else if (attr.GetType() == typeof(CLSCompliantAttribute))
                    Console.WriteLine("Module {0} {1} CLSCompliant.",
                        module.Name,
                        ((CLSCompliantAttribute)attr).IsCompliant ?
                            "is" : "is not");
            }
        }
    }
}

/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

open System
open System.ComponentModel

// Assign some attributes to the module.
[<``module``: Description "A sample description">]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[<``module``: CLSCompliant false>]
do ()

type DemoClass = class end

// Get the Module type to access its metadata.
let ilmodule = typeof<DemoClass>.Module

// Iterate through all the attributes for the module.
for attr in Attribute.GetCustomAttributes ilmodule do
    match attr with
    // Check for the Description attribute.
    | :? DescriptionAttribute as attr ->
        printfn $"Module {ilmodule.Name} has the description \"{attr.Description}\"."
                
    // Check for the CLSCompliant attribute.
    | :? CLSCompliantAttribute as attr ->
        printfn $"""Module {ilmodule.Name} {if attr.IsCompliant then "is" else "is not"} CLSCompliant."""
    | _ -> ()
    
// Output:
// Module CustAttrs2CS.exe is not CLSCompliant.
// Module CustAttrs2CS.exe has the description "A sample description".

Imports System.Reflection
Imports System.ComponentModel

' Give the Module some attributes.
<Module: Description("A sample description")> 

' Make the CLSCompliant attribute False.
' The CLSCompliant attribute is applicable for /target:module.
<Module: CLSCompliant(False)> 

Module DemoModule

    Sub Main()
        ' Get the Module type to access its metadata.
        Dim modType As Reflection.Module = GetType(DemoModule).Module
        Dim attr As Attribute
        ' Iterate through all the attributes for the module.
        For Each attr In Attribute.GetCustomAttributes(modType)
            ' Check for the Description attribute.
            If TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Module {0} has the description ""{1}"".", _
                    modType.Name, descAttr.Description)

            ' Check for the CLSCompliant attribute.
            ElseIf TypeOf attr Is CLSCompliantAttribute Then
                ' Convert the attribute to access its data.
                Dim CLSCompAttr As CLSCompliantAttribute = _
                    CType(attr, CLSCompliantAttribute)
                Dim strCompliant As String
                If CLSCompAttr.IsCompliant Then
                    strCompliant = "is"
                Else
                    strCompliant = "is not"
                End If
                Console.WriteLine("Module {0} {1} CLSCompliant.", _
                    modType.Name, strCompliant)
            End If
        Next
    End Sub
End Module

' Output:
' Module CustAttrs2VB.exe has the description "A sample description".
' Module CustAttrs2VB.exe is not CLSCompliant.

GetCustomAttributes(MemberInfo)

检索应用于类型的成员的自定义属性的数组。 参数指定成员。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::MemberInfo ^ element);

public static Attribute[] GetCustomAttributes (System.Reflection.MemberInfo element);

static member GetCustomAttributes : System.Reflection.MemberInfo -> Attribute[]

Public Shared Function GetCustomAttributes (element As MemberInfo) As Attribute()

参数

element

MemberInfo

一个从 MemberInfo 类派生的对象，该类描述类的构造函数、事件、字段、方法或属性成员。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 为 null。

NotSupportedException

element 不是构造函数、方法、属性、事件、类型或字段。

TypeLoadException

无法加载自定义属性类型。

示例

下面的代码示例演示了如何使用 GetCustomAttribute作为 MemberInfo 参数。

using namespace System;
using namespace System::Reflection;
using namespace System::Security;
using namespace System::Runtime::InteropServices;

namespace CustAttrs4CS
{
   // Create a class for Win32 imported unmanaged functions.
   public ref class Win32
   {
   public:

      [DllImport("user32.dll", CharSet = CharSet::Unicode)]
      static int MessageBox( int hWnd, String^ text, String^ caption, UInt32 type );
   };

   public ref class AClass
   {
   public:

      // Add some attributes to the Win32CallMethod.

      [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
      void Win32CallMethod()
      {
         Win32::MessageBox( 0, "This is an unmanaged call.", "Be Careful!", 0 );
      }

   };

   ref class DemoClass
   {
   public:
      static void Main()
      {
         // Get the Class type to access its metadata.
         Type^ clsType = AClass::typeid;

         // Get the type information for the Win32CallMethod.
         MethodInfo^ mInfo = clsType->GetMethod( "Win32CallMethod" );
         if ( mInfo != nullptr )
         {
            // Iterate through all the attributes for the method.
            System::Collections::IEnumerator^ myEnum3 = Attribute::GetCustomAttributes( mInfo )->GetEnumerator();
            while ( myEnum3->MoveNext() )
            {
               Attribute^ attr = safe_cast<Attribute^>(myEnum3->Current);

               // Check for the Obsolete attribute.
               if ( attr->GetType() == ObsoleteAttribute::typeid )
               {
                  Console::WriteLine( "Method {0} is obsolete. "
                  "The message is:", mInfo->Name );
                  Console::WriteLine( (dynamic_cast<ObsoleteAttribute^>(attr))->Message );
               }
               // Check for the SuppressUnmanagedCodeSecurity attribute.
               else

               // Check for the SuppressUnmanagedCodeSecurity attribute.
               if ( attr->GetType() == SuppressUnmanagedCodeSecurityAttribute::typeid )
               {
                  Console::WriteLine( "This method calls unmanaged code "
                  "with no security check." );
                  Console::WriteLine( "Please do not use unless absolutely necessary." );
                  AClass^ myCls = gcnew AClass;
                  myCls->Win32CallMethod();
               }
            }
         }
      }
   };
}


/*
 * Output:
 * Method Win32CallMethod is obsolete. The message is:
 * This method is obsolete. Use managed MsgBox instead.
 * This method calls unmanaged code with no security check.
 * Please do not use unless absolutely necessary.
 */

using System;
using System.Reflection;
using System.Security;
using System.Runtime.InteropServices;

namespace CustAttrs4CS
{

    // Define an enumeration of Win32 unmanaged types
    public enum UnmanagedType
    {
        User,
        GDI,
        Kernel,
        Shell,
        Networking,
        Multimedia
    }

    // Define the Unmanaged attribute.
    public class UnmanagedAttribute : Attribute
    {
        // Storage for the UnmanagedType value.
        protected UnmanagedType thisType;

        // Set the unmanaged type in the constructor.
        public UnmanagedAttribute(UnmanagedType type)
        {
            thisType = type;
        }

        // Define a property to get and set the UnmanagedType value.
        public UnmanagedType Win32Type
        {
            get { return thisType; }
            set { thisType = Win32Type; }
        }
    }

    // Create a class for an imported Win32 unmanaged function.
    public class Win32 {
        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
        public static extern int MessageBox(int hWnd, String text,
            String caption, uint type);
    }

    public class AClass {
        // Add some attributes to Win32CallMethod.
        [Obsolete("This method is obsolete. Use managed MsgBox instead.")]
        [Unmanaged(UnmanagedType.User)]
        public void Win32CallMethod()
        {
            Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0);
        }
    }

    class DemoClass {
        static void Main(string[] args)
            {
            // Get the AClass type to access its metadata.
            Type clsType = typeof(AClass);
            // Get the type information for Win32CallMethod.
            MethodInfo mInfo = clsType.GetMethod("Win32CallMethod");
            if (mInfo != null)
            {
                // Iterate through all the attributes of the method.
                foreach(Attribute attr in
                    Attribute.GetCustomAttributes(mInfo)) {
                    // Check for the Obsolete attribute.
                    if (attr.GetType() == typeof(ObsoleteAttribute))
                    {
                        Console.WriteLine("Method {0} is obsolete. " +
                            "The message is:",
                            mInfo.Name);
                        Console.WriteLine("  \"{0}\"",
                            ((ObsoleteAttribute)attr).Message);
                    }

                    // Check for the Unmanaged attribute.
                    else if (attr.GetType() == typeof(UnmanagedAttribute))
                    {
                        Console.WriteLine(
                            "This method calls unmanaged code.");
                        Console.WriteLine(
                            String.Format("The Unmanaged attribute type is {0}.",
                                          ((UnmanagedAttribute)attr).Win32Type));
                        AClass myCls = new AClass();
                        myCls.Win32CallMethod();
                    }
                }
            }
        }
    }
}

/*

This code example produces the following results.

First, the compilation yields the warning, "... This method is
obsolete. Use managed MsgBox instead."
Second, execution yields a message box with a title of "Caution!"
and message text of "This is an unmanaged call."
Third, the following text is displayed in the console window:

Method Win32CallMethod is obsolete. The message is:
  "This method is obsolete. Use managed MsgBox instead."
This method calls unmanaged code.
The Unmanaged attribute type is User.

*/

open System
open System.Runtime.InteropServices

// Define an enumeration of Win32 unmanaged types
type UnmanagedType =
    | User = 0
    | GDI = 1
    | Kernel = 2
    | Shell = 3
    | Networking = 4
    | Multimedia = 5

// Define the Unmanaged attribute.
type UnmanagedAttribute(unmanagedType) =
    inherit Attribute()
    
    // Define a property to get and set the UnmanagedType value.
    member val Win32Type = unmanagedType with get, set

// Create a module for an imported Win32 unmanaged function.
module Win32 =
    [<DllImport("user32.dll", CharSet = CharSet.Unicode)>]
    extern int MessageBox(IntPtr hWnd, String text, String caption, uint ``type``)

type AClass() =
    // Add some attributes to Win32CallMethod.
    [<Obsolete "This method is obsolete. Use managed MsgBox instead.">]
    [<Unmanaged(UnmanagedType.User)>]
    member _.Win32CallMethod () =
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0u)

// Get the AClass type to access its metadata.
let clsType = typeof<AClass>
// Get the type information for Win32CallMethod.
let mInfo = clsType.GetMethod "Win32CallMethod"
if mInfo <> null then
    // Iterate through all the attributes of the method.
    for attr in Attribute.GetCustomAttributes mInfo do
        match attr with 
        // Check for the Obsolete attribute.
        | :? ObsoleteAttribute as attr ->
            printfn $"Method {mInfo.Name} is obsolete. The message is:"
            printfn $"  \"{attr.Message}\""

        // Check for the Unmanaged attribute.
        | :? UnmanagedAttribute as attr ->
            printfn "This method calls unmanaged code."
            printfn $"The Unmanaged attribute type is {attr.Win32Type}."
            let myCls = AClass()
            myCls.Win32CallMethod() |> ignore
        | _ -> ()

// This code example produces the following results.
//
// First, the compilation yields the warning, "... This method is
// obsolete. Use managed MsgBox instead."
// Second, execution yields a message box with a title of "Caution!"
// and message text of "This is an unmanaged call."
// Third, the following text is displayed in the console window:

// Method Win32CallMethod is obsolete. The message is:
//   "This method is obsolete. Use managed MsgBox instead."
// This method calls unmanaged code.
// The Unmanaged attribute type is User.

Imports System.Reflection
Imports System.Security
Imports System.Runtime.InteropServices

' Define an enumeration of Win32 unmanaged types
Public Enum UnmanagedType
    User
    GDI
    Kernel
    Shell
    Networking
    Multimedia
End Enum 'UnmanagedType

' Define the Unmanaged attribute.
Public Class UnmanagedAttribute 
             Inherits Attribute

    ' Storage for the UnmanagedType value.
    Protected thisType As UnmanagedType
    
    ' Set the unmanaged type in the constructor.
    Public Sub New(ByVal type As UnmanagedType) 
        thisType = type
    End Sub
    
    ' Define a property to get and set the UnmanagedType value.
    Public Property Win32Type() As UnmanagedType 
        Get
            Return thisType
        End Get
        Set
            thisType = Win32Type
        End Set
    End Property
End Class

' Create a class for an imported Win32 unmanaged function.
Public Class Win32
    <DllImport("user32.dll", CharSet:=CharSet.Unicode)> _
    Public Shared Function MessageBox(ByVal hWnd As Integer, _
                                      ByVal Text As String, _
                                      ByVal caption As String, _
                                      ByVal type As Integer) As Integer
    End Function 'MessageBox
End Class

Public Class AClass
    ' Add some attributes to Win32CallMethod.
    <Obsolete("This method is obsolete. Use managed MsgBox instead."), _
     Unmanaged(UnmanagedType.User)>  _
    Public Sub Win32CallMethod() 
        Win32.MessageBox(0, "This is an unmanaged call.", "Caution!", 0)    
    End Sub
End Class

Class DemoClass
    Shared Sub Main(ByVal args() As String) 
        ' Get the AClass type to access its metadata.
        Dim clsType As Type = GetType(AClass)
        ' Get the type information for Win32CallMethod.
        Dim mInfo As MethodInfo = clsType.GetMethod("Win32CallMethod")
        If Not (mInfo Is Nothing) Then
            ' Iterate through all the attributes of the method.
            Dim attr As Attribute
            For Each attr In  Attribute.GetCustomAttributes(mInfo)
                ' Check for the Obsolete attribute.
                If attr.GetType().Equals(GetType(ObsoleteAttribute)) Then
                    Console.WriteLine("Method {0} is obsolete. The message is:", mInfo.Name)
                    Console.WriteLine("  ""{0}""", CType(attr, ObsoleteAttribute).Message)
                ' Check for the Unmanaged attribute.
                ElseIf attr.GetType().Equals(GetType(UnmanagedAttribute)) Then
                    Console.WriteLine("This method calls unmanaged code.")
                    Console.WriteLine( _
                            String.Format("The Unmanaged attribute type is {0}.", _
                            CType(attr, UnmanagedAttribute).Win32Type))
                    Dim myCls As New AClass()
                    myCls.Win32CallMethod()
                End If
            Next attr
        End If
    End Sub
End Class

'
'This code example produces the following results. 
'
'First, the compilation yields the warning, "... This method is 
'obsolete. Use managed MsgBox instead."
'Second, execution yields a message box with a title of "Caution!" 
'and message text of "This is an unmanaged call." 
'Third, the following text is displayed in the console window:
'
'Method Win32CallMethod is obsolete. The message is:
'  "This method is obsolete. Use managed MsgBox instead."
'This method calls unmanaged code.
'The Unmanaged attribute type is User.
'

注解

返回值包含上级 element对象的自定义属性。

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回方法、构造函数和类型的安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的.NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Assembly)

检索一个数组，它由应用于程序集的自定义属性组成。 参数指定程序集。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Assembly ^ element);

public static Attribute[] GetCustomAttributes (System.Reflection.Assembly element);

static member GetCustomAttributes : System.Reflection.Assembly -> Attribute[]

Public Shared Function GetCustomAttributes (element As Assembly) As Attribute()

参数

element

Assembly

一个派生自 Assembly 类的对象，用于描述模块的可重用集合。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 为 null。

示例

以下示例检索在当前程序集中找到的自定义属性。

using namespace System;
using namespace System::Reflection;

[assembly:AssemblyTitle("CustAttrs1CPP")];
[assembly:AssemblyDescription("GetCustomAttributes() Demo")];
[assembly:AssemblyCompany("Microsoft")];

ref class Example
{};

static void main()
{
    Type^ clsType = Example::typeid;

    // Get the Assembly type to access its metadata.
    Assembly^ assy = clsType->Assembly;

    // Iterate through the attributes for the assembly.
    System::Collections::IEnumerator^ myEnum = Attribute::GetCustomAttributes( assy )->GetEnumerator();
    while ( myEnum->MoveNext() )
    {
       Attribute^ attr = safe_cast<Attribute^>(myEnum->Current);

       // Check for the AssemblyTitle attribute.
       if ( attr->GetType() == AssemblyTitleAttribute::typeid )
          Console::WriteLine( "Assembly title is \"{0}\".", (dynamic_cast<AssemblyTitleAttribute^>(attr))->Title );
          // Check for the AssemblyDescription attribute.
       else
          // Check for the AssemblyDescription attribute.
          if ( attr->GetType() == AssemblyDescriptionAttribute::typeid )
             Console::WriteLine( "Assembly description is \"{0}\".", (dynamic_cast<AssemblyDescriptionAttribute^>(attr))->Description );
          // Check for the AssemblyCompany attribute.
          else if ( attr->GetType() == AssemblyCompanyAttribute::typeid )
             Console::WriteLine( "Assembly company is {0}.", (dynamic_cast<AssemblyCompanyAttribute^>(attr))->Company );
    }
}
// The example displays the following output:
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.
//     Assembly title is "CustAttrs1CPP".

using System;
using System.Reflection;

[assembly: AssemblyTitle("CustAttrs1CS")]
[assembly: AssemblyDescription("GetCustomAttributes() Demo")]
[assembly: AssemblyCompany("Microsoft")]

class Example {
    static void Main() {
        // Get the Assembly object to access its metadata.
        Assembly assy = typeof(Example).Assembly;

        // Iterate through the attributes for the assembly.
        foreach(Attribute attr in Attribute.GetCustomAttributes(assy)) {
            // Check for the AssemblyTitle attribute.
            if (attr.GetType() == typeof(AssemblyTitleAttribute))
                Console.WriteLine("Assembly title is \"{0}\".",
                    ((AssemblyTitleAttribute)attr).Title);

            // Check for the AssemblyDescription attribute.
            else if (attr.GetType() ==
                typeof(AssemblyDescriptionAttribute))
                Console.WriteLine("Assembly description is \"{0}\".",
                    ((AssemblyDescriptionAttribute)attr).Description);

            // Check for the AssemblyCompany attribute.
            else if (attr.GetType() == typeof(AssemblyCompanyAttribute))
                Console.WriteLine("Assembly company is {0}.",
                    ((AssemblyCompanyAttribute)attr).Company);
        }
   }
}
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

open System
open System.Reflection

[<assembly: AssemblyTitle "CustAttrs1CS">]
[<assembly: AssemblyDescription "GetCustomAttributes() Demo">]
[<assembly: AssemblyCompany"Microsoft">]
do ()

type Example = class end

// Get the Assembly object to access its metadata.
let assembly = typeof<Example>.Assembly

// Iterate through the attributes for the assembly.
for attr in Attribute.GetCustomAttributes assembly do
    match attr with
    // Check for the AssemblyTitle attribute.
    | :? AssemblyTitleAttribute as attr ->    
        printfn $"Assembly title is \"{attr.Title}\"."
    // Check for the AssemblyDescription attribute.
    | :? AssemblyDescriptionAttribute as attr ->
        printfn $"Assembly description is \"{attr.Description}\"."
    // Check for the AssemblyCompany attribute.
    | :? AssemblyCompanyAttribute as attr ->
        printfn $"Assembly company is {attr.Company}."
    | _ -> ()
    
// The example displays the following output:
//     Assembly title is "CustAttrs1CS".
//     Assembly description is "GetCustomAttributes() Demo".
//     Assembly company is Microsoft.

Imports System.Reflection

<Assembly: AssemblyTitle("CustAttrs1VB")> 
<Assembly: AssemblyDescription("GetCustomAttributes() Demo")> 
<Assembly: AssemblyCompany("Microsoft")> 

Module Example
    Sub Main()
        ' Get the Assembly type to access its metadata.
        Dim assy As Reflection.Assembly = GetType(Example).Assembly

        ' Iterate through all the attributes for the assembly.
        For Each attr As Attribute In Attribute.GetCustomAttributes(assy)
            ' Check for the AssemblyTitle attribute.
            If TypeOf attr Is AssemblyTitleAttribute Then
                ' Convert the attribute to access its data.
                Dim attrTitle As AssemblyTitleAttribute = _
                    CType(attr, AssemblyTitleAttribute)
                Console.WriteLine("Assembly title is ""{0}"".", _
                    attrTitle.Title)

            ' Check for the AssemblyDescription attribute.
            ElseIf TypeOf attr Is AssemblyDescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim attrDesc As AssemblyDescriptionAttribute = _
                    CType(attr, AssemblyDescriptionAttribute)
                Console.WriteLine("Assembly description is ""{0}"".", _
                    attrDesc.Description)

            ' Check for the AssemblyCompany attribute.
            ElseIf TypeOf attr Is AssemblyCompanyAttribute Then
                ' Convert the attribute to access its data.
                Dim attrComp As AssemblyCompanyAttribute = _
                    CType(attr, AssemblyCompanyAttribute)
                Console.WriteLine("Assembly company is {0}.", _
                    attrComp.Company)
            End If
        Next
    End Sub
End Module
' The example displays the following output:
'     Assembly company is Microsoft.
'     Assembly description is "GetCustomAttributes() Demo".
'     Assembly title is "CustAttrs1VB".

注解

备注

从 .NET Framework 版本 2.0 开始，如果属性以新的元数据格式存储，此方法将返回安全属性。 使用版本 2.0 或更高版本编译的程序集使用新格式。 使用早期版本的.NET Framework编译的动态程序集和程序集使用旧的 XML 格式。 请参阅 发出声明性安全属性。

GetCustomAttributes(Module, Boolean)

检索应用于模块的自定义属性的数组。 参数指定模块及忽略的搜索选项。

public:
 static cli::array <Attribute ^> ^ GetCustomAttributes(System::Reflection::Module ^ element, bool inherit);

public static Attribute[] GetCustomAttributes (System.Reflection.Module element, bool inherit);

static member GetCustomAttributes : System.Reflection.Module * bool -> Attribute[]

Public Shared Function GetCustomAttributes (element As Module, inherit As Boolean) As Attribute()

参数

element

Module

一个从 Module 类派生的对象，该类描述可移植的可执行文件。

inherit

Boolean

此参数被忽略，并且不会影响此方法的操作。

返回

Attribute[]

一个 Attribute 数组，其中包含应用于 element 的自定义属性；如果不存在任何此类自定义属性，则为空数组。

例外

ArgumentNullException

element 或 attributeType 为 null。

示例

下面的代码示例演示了采用参数的用法GetCustomAttributesModule。

using namespace System;
using namespace System::Reflection;
using namespace System::ComponentModel;

// Assign some attributes to the module.
// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:Description("A sample description")];
[module:CLSCompliant(false)];
namespace CustAttrs2CS
{
   ref class DemoClass
   {
   public:
      static void Main()
      {
         Type^ clsType = DemoClass::typeid;

         // Get the Module type to access its metadata.
         Module^ module = clsType->Module;

         // Iterate through all the attributes for the module.
         System::Collections::IEnumerator^ myEnum1 = Attribute::GetCustomAttributes( module )->GetEnumerator();
         while ( myEnum1->MoveNext() )
         {
            Attribute^ attr = safe_cast<Attribute^>(myEnum1->Current);

            // Check for the Description attribute.
            if ( attr->GetType() == DescriptionAttribute::typeid )
                        Console::WriteLine( "Module {0} has the description \"{1}\".", module->Name, (dynamic_cast<DescriptionAttribute^>(attr))->Description );
            // Check for the CLSCompliant attribute.
            else

            // Check for the CLSCompliant attribute.
            if ( attr->GetType() == CLSCompliantAttribute::typeid )
                        Console::WriteLine( "Module {0} {1} CLSCompliant.", module->Name, (dynamic_cast<CLSCompliantAttribute^>(attr))->IsCompliant ? (String^)"is" : "is not" );
         }
      }
   };
}


/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

using System;
using System.Reflection;
using System.ComponentModel;

// Assign some attributes to the module.
[module:Description("A sample description")]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[module:CLSCompliant(false)]

namespace CustAttrs2CS {
    class DemoClass {
        static void Main(string[] args) {
            Type clsType = typeof(DemoClass);
            // Get the Module type to access its metadata.
            Module module = clsType.Module;

            // Iterate through all the attributes for the module.
            foreach(Attribute attr in Attribute.GetCustomAttributes(module)) {
                // Check for the Description attribute.
                if (attr.GetType() == typeof(DescriptionAttribute))
                    Console.WriteLine("Module {0} has the description " +
                        "\"{1}\".", module.Name,
                        ((DescriptionAttribute)attr).Description);
                // Check for the CLSCompliant attribute.
                else if (attr.GetType() == typeof(CLSCompliantAttribute))
                    Console.WriteLine("Module {0} {1} CLSCompliant.",
                        module.Name,
                        ((CLSCompliantAttribute)attr).IsCompliant ?
                            "is" : "is not");
            }
        }
    }
}

/*
 * Output:
 * Module CustAttrs2CS.exe is not CLSCompliant.
 * Module CustAttrs2CS.exe has the description "A sample description".
 */

open System
open System.ComponentModel

// Assign some attributes to the module.
[<``module``: Description "A sample description">]

// Set the module's CLSCompliant attribute to false
// The CLSCompliant attribute is applicable for /target:module.
[<``module``: CLSCompliant false>]
do ()

type DemoClass = class end

// Get the Module type to access its metadata.
let ilmodule = typeof<DemoClass>.Module

// Iterate through all the attributes for the module.
for attr in Attribute.GetCustomAttributes ilmodule do
    match attr with
    // Check for the Description attribute.
    | :? DescriptionAttribute as attr ->
        printfn $"Module {ilmodule.Name} has the description \"{attr.Description}\"."
                
    // Check for the CLSCompliant attribute.
    | :? CLSCompliantAttribute as attr ->
        printfn $"""Module {ilmodule.Name} {if attr.IsCompliant then "is" else "is not"} CLSCompliant."""
    | _ -> ()
    
// Output:
// Module CustAttrs2CS.exe is not CLSCompliant.
// Module CustAttrs2CS.exe has the description "A sample description".

Imports System.Reflection
Imports System.ComponentModel

' Give the Module some attributes.
<Module: Description("A sample description")> 

' Make the CLSCompliant attribute False.
' The CLSCompliant attribute is applicable for /target:module.
<Module: CLSCompliant(False)> 

Module DemoModule

    Sub Main()
        ' Get the Module type to access its metadata.
        Dim modType As Reflection.Module = GetType(DemoModule).Module
        Dim attr As Attribute
        ' Iterate through all the attributes for the module.
        For Each attr In Attribute.GetCustomAttributes(modType)
            ' Check for the Description attribute.
            If TypeOf attr Is DescriptionAttribute Then
                ' Convert the attribute to access its data.
                Dim descAttr As DescriptionAttribute = _
                    CType(attr, DescriptionAttribute)
                Console.WriteLine("Module {0} has the description ""{1}"".", _
                    modType.Name, descAttr.Description)

            ' Check for the CLSCompliant attribute.
            ElseIf TypeOf attr Is CLSCompliantAttribute Then
                ' Convert the attribute to access its data.
                Dim CLSCompAttr As CLSCompliantAttribute = _
                    CType(attr, CLSCompliantAttribute)
                Dim strCompliant As String
                If CLSCompAttr.IsCompliant Then
                    strCompliant = "is"
                Else
                    strCompliant = "is not"
                End If
                Console.WriteLine("Module {0} {1} CLSCompliant.", _
                    modType.Name, strCompliant)
            End If
        Next
    End Sub
End Module

' Output:
' Module CustAttrs2VB.exe has the description "A sample description".
' Module CustAttrs2VB.exe is not CLSCompliant.

注解

返回值包含父级的自定义属性 element （如果 inherit 为 true）。