CustomAttributeBuilder 类

项目
08/17/2007

帮助生成自定义属性。

**命名空间:**System.Reflection.Emit
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
<ComVisibleAttribute(True)> _
<ClassInterfaceAttribute(ClassInterfaceType.None)> _
Public Class CustomAttributeBuilder
    Implements _CustomAttributeBuilder
用法
Dim instance As CustomAttributeBuilder

[ComVisibleAttribute(true)] 
[ClassInterfaceAttribute(ClassInterfaceType.None)] 
public class CustomAttributeBuilder : _CustomAttributeBuilder

[ComVisibleAttribute(true)] 
[ClassInterfaceAttribute(ClassInterfaceType::None)] 
public ref class CustomAttributeBuilder : _CustomAttributeBuilder

/** @attribute ComVisibleAttribute(true) */ 
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ 
public class CustomAttributeBuilder implements _CustomAttributeBuilder

ComVisibleAttribute(true) 
ClassInterfaceAttribute(ClassInterfaceType.None) 
public class CustomAttributeBuilder implements _CustomAttributeBuilder

备注

提示

应用于此类的 HostProtectionAttribute 属性 (Attribute) 具有以下 Resources 属性 (Property) 值：MayLeakOnAbort。HostProtectionAttribute 不影响桌面应用程序（这些应用程序通常通过双击图标、键入命令或在浏览器中输入 URL 来启动）。有关更多信息，请参见 HostProtectionAttribute 类或 SQL Server 编程和宿主保护属性。

使用由构造函数返回的 CustomAttributeBuilder 对象来描述自定义属性。通过调用某个生成器实例上的 SetCustomAttribute 方法将 CustomAttribute 关联到该生成器实例。例如，通过提供 AssemblyCultureAttribute 的构造函数及其参数，创建 CustomAttributeBuilder 以描述 AssemblyCultureAttribute 的实例。然后调用 AssemblyBuilder 上的 SetCustomAttribute 以建立关联。

示例

下面的代码阐释了如何使用 CustomAttributeBuilder。

Imports System
Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _


' We will apply this custom attribute to our dynamic type.
Public Class ClassCreator

   Inherits Attribute
   
   Private creator As String
   
   Public ReadOnly Property GetCreator() As String
      Get
         Return creator
      End Get
   End Property
   
   
   Public Sub New(name As String)
      Me.creator = name
   End Sub 'New

End Class 'ClassCreator
 _ 

' We will apply this dynamic attribute to our dynamic method.
Public Class DateLastUpdated

   Inherits Attribute
   
   Private dateUpdated As String
   
   Public ReadOnly Property GetDateUpdated() As String
      Get
         Return dateUpdated
      End Get
   End Property
   
   
   Public Sub New(theDate As String)
      Me.dateUpdated = theDate
   End Sub 'New

End Class 'DateLastUpdated
 _ 

Class MethodBuilderCustomAttributesDemo
   
   Public Shared Function BuildTypeWithCustomAttributesOnMethod() As Type
      
      Dim currentDomain As AppDomain = Thread.GetDomain()
      
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyAssembly"
      
      Dim myAsmBuilder As AssemblyBuilder = currentDomain.DefineDynamicAssembly(myAsmName, _
                            AssemblyBuilderAccess.Run)
      
      Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyModule")
      
      ' First, we'll build a type with a custom attribute attached.
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("MyType", _
                            TypeAttributes.Public)
      
      Dim ctorParams() As Type = {GetType(String)}
      Dim classCtorInfo As ConstructorInfo = GetType(ClassCreator).GetConstructor(ctorParams)
      
      Dim myCABuilder As New CustomAttributeBuilder(classCtorInfo, _
                        New Object() {"Joe Programmer"})
      
      myTypeBuilder.SetCustomAttribute(myCABuilder)
      
      ' Now, let's build a method and add a custom attribute to it.
      Dim myMethodBuilder As MethodBuilder = myTypeBuilder.DefineMethod("HelloWorld", _
                    MethodAttributes.Public, Nothing, New Type() {})
      
      ctorParams = New Type() {GetType(String)}
      classCtorInfo = GetType(DateLastUpdated).GetConstructor(ctorParams)
      
      Dim myCABuilder2 As New CustomAttributeBuilder(classCtorInfo, _
                        New Object() {DateTime.Now.ToString()})
      
      myMethodBuilder.SetCustomAttribute(myCABuilder2)
      
      Dim myIL As ILGenerator = myMethodBuilder.GetILGenerator()
      
      myIL.EmitWriteLine("Hello, world!")
      myIL.Emit(OpCodes.Ret)
      
      Return myTypeBuilder.CreateType()

   End Function 'BuildTypeWithCustomAttributesOnMethod
    
   
   Public Shared Sub Main()
      
      Dim myType As Type = BuildTypeWithCustomAttributesOnMethod()
      
      Dim myInstance As Object = Activator.CreateInstance(myType)
      
      Dim customAttrs As Object() = myType.GetCustomAttributes(True)
      
      Console.WriteLine("Custom Attributes for Type 'MyType':")
      
      Dim attrVal As Object = Nothing
      
      Dim customAttr As Object
      For Each customAttr In  customAttrs
         attrVal = GetType(ClassCreator).InvokeMember("GetCreator", _
                        BindingFlags.GetProperty, _
                        Nothing, customAttr, New Object() {})
         Console.WriteLine("-- Attribute: [{0} = ""{1}""]", customAttr, attrVal)
      Next customAttr
      
      Console.WriteLine("Custom Attributes for Method 'HelloWorld()' in 'MyType':")
      
      customAttrs = myType.GetMember("HelloWorld")(0).GetCustomAttributes(True)
      
      For Each customAttr In  customAttrs
         attrVal = GetType(DateLastUpdated).InvokeMember("GetDateUpdated", _
                        BindingFlags.GetProperty, _
                        Nothing, customAttr, New Object() {})
         Console.WriteLine("-- Attribute: [{0} = ""{1}""]", customAttr, attrVal)
      Next customAttr
      
      Console.WriteLine("---")
      
      Console.WriteLine(myType.InvokeMember("HelloWorld", BindingFlags.InvokeMethod, _
                        Nothing, myInstance, New Object() {}))
   End Sub 'Main

End Class 'MethodBuilderCustomAttributesDemo

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;


// We will apply this custom attribute to our dynamic type.
public class ClassCreator: Attribute

{
   private string creator;
   public string Creator 
   {
    get
    {
       return creator;
    }
   }    

   public ClassCreator(string name)
   {
      this.creator = name;
   }

}

// We will apply this dynamic attribute to our dynamic method.
public class DateLastUpdated: Attribute

{
   private string dateUpdated;
   public string DateUpdated
   {
    get
    {
       return dateUpdated;
    }
   }

   public DateLastUpdated(string theDate)
   {
    this.dateUpdated = theDate;
   } 

}

class MethodBuilderCustomAttributesDemo

{

   public static Type BuildTypeWithCustomAttributesOnMethod()
   {
    
    AppDomain currentDomain = Thread.GetDomain();
    
    AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyAssembly";

    AssemblyBuilder myAsmBuilder = currentDomain.DefineDynamicAssembly(
                       myAsmName, AssemblyBuilderAccess.Run);

    ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule("MyModule");

    // First, we'll build a type with a custom attribute attached.

    TypeBuilder myTypeBuilder = myModBuilder.DefineType("MyType",
                        TypeAttributes.Public);
    
    Type[] ctorParams = new Type[] { typeof(string) };
    ConstructorInfo classCtorInfo = typeof(ClassCreator).GetConstructor(ctorParams);

    CustomAttributeBuilder myCABuilder = new CustomAttributeBuilder(
                        classCtorInfo,
                        new object[] { "Joe Programmer" });

    myTypeBuilder.SetCustomAttribute(myCABuilder);

    // Now, let's build a method and add a custom attribute to it.

    MethodBuilder myMethodBuilder = myTypeBuilder.DefineMethod("HelloWorld",
                    MethodAttributes.Public,
                    null,
                    new Type[] { });

    ctorParams = new Type[] { typeof(string) };
    classCtorInfo = typeof(DateLastUpdated).GetConstructor(ctorParams);

    CustomAttributeBuilder myCABuilder2 = new CustomAttributeBuilder(
                        classCtorInfo,
                        new object[] { DateTime.Now.ToString() });

    myMethodBuilder.SetCustomAttribute(myCABuilder2);

    ILGenerator myIL = myMethodBuilder.GetILGenerator();

    myIL.EmitWriteLine("Hello, world!");
    myIL.Emit(OpCodes.Ret);

    return myTypeBuilder.CreateType();
    
   }

   public static void Main() 
   {

    Type myType = BuildTypeWithCustomAttributesOnMethod();

    object myInstance = Activator.CreateInstance(myType);

    object[] customAttrs = myType.GetCustomAttributes(true);

    Console.WriteLine("Custom Attributes for Type 'MyType':");

    object attrVal = null;

    foreach (object customAttr in customAttrs) 
    {
       attrVal = typeof(ClassCreator).InvokeMember("Creator", 
                      BindingFlags.GetProperty,
                      null, customAttr, new object[] { });
       Console.WriteLine("-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal);
        }

    Console.WriteLine("Custom Attributes for Method 'HelloWorld()' in 'MyType':");

    customAttrs = myType.GetMember("HelloWorld")[0].GetCustomAttributes(true);  

    foreach (object customAttr in customAttrs) 
    {
       attrVal = typeof(DateLastUpdated).InvokeMember("DateUpdated", 
                      BindingFlags.GetProperty,
                      null, customAttr, new object[] { });
       Console.WriteLine("-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal);
        }

    Console.WriteLine("---");

    Console.WriteLine(myType.InvokeMember("HelloWorld",
              BindingFlags.InvokeMethod,
              null, myInstance, new object[] { }));
                           
    
   }

}

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;

// We will apply this custom attribute to our dynamic type.
public ref class ClassCreator: public Attribute
{
private:
   String^ creator;

public:

   property String^ Creator 
   {
      String^ get()
      {
         return creator;
      }

   }
   ClassCreator( String^ name )
   {
      this->creator = name;
   }

};


// We will apply this dynamic attribute to our dynamic method.
public ref class DateLastUpdated: public Attribute
{
private:
   String^ dateUpdated;

public:

   property String^ DateUpdated 
   {
      String^ get()
      {
         return dateUpdated;
      }

   }
   DateLastUpdated( String^ theDate )
   {
      this->dateUpdated = theDate;
   }

};

Type^ BuildTypeWithCustomAttributesOnMethod()
{
   AppDomain^ currentDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew AssemblyName;
   myAsmName->Name = "MyAssembly";
   AssemblyBuilder^ myAsmBuilder = currentDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::Run );
   ModuleBuilder^ myModBuilder = myAsmBuilder->DefineDynamicModule( "MyModule" );
   
   // First, we'll build a type with a custom attribute attached.
   TypeBuilder^ myTypeBuilder = myModBuilder->DefineType( "MyType", TypeAttributes::Public );
   array<Type^>^temp6 = {String::typeid};
   array<Type^>^ctorParams = temp6;
   ConstructorInfo^ classCtorInfo = ClassCreator::typeid->GetConstructor( ctorParams );
   array<Object^>^temp0 = {"Joe Programmer"};
   CustomAttributeBuilder^ myCABuilder = gcnew CustomAttributeBuilder( classCtorInfo,temp0 );
   myTypeBuilder->SetCustomAttribute( myCABuilder );
   
   // Now, let's build a method and add a custom attribute to it.
   array<Type^>^temp1 = gcnew array<Type^>(0);
   MethodBuilder^ myMethodBuilder = myTypeBuilder->DefineMethod( "HelloWorld", MethodAttributes::Public, nullptr, temp1 );
   array<Type^>^temp7 = {String::typeid};
   ctorParams = temp7;
   classCtorInfo = DateLastUpdated::typeid->GetConstructor( ctorParams );
   array<Object^>^temp2 = {DateTime::Now.ToString()};
   CustomAttributeBuilder^ myCABuilder2 = gcnew CustomAttributeBuilder( classCtorInfo,temp2 );
   myMethodBuilder->SetCustomAttribute( myCABuilder2 );
   ILGenerator^ myIL = myMethodBuilder->GetILGenerator();
   myIL->EmitWriteLine( "Hello, world!" );
   myIL->Emit( OpCodes::Ret );
   return myTypeBuilder->CreateType();
}

int main()
{
   Type^ myType = BuildTypeWithCustomAttributesOnMethod();
   Object^ myInstance = Activator::CreateInstance( myType );
   array<Object^>^customAttrs = myType->GetCustomAttributes( true );
   Console::WriteLine( "Custom Attributes for Type 'MyType':" );
   Object^ attrVal = nullptr;
   System::Collections::IEnumerator^ myEnum = customAttrs->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ customAttr = safe_cast<Object^>(myEnum->Current);
      array<Object^>^temp3 = gcnew array<Object^>(0);
      attrVal = ClassCreator::typeid->InvokeMember( "Creator", BindingFlags::GetProperty, nullptr, customAttr, temp3 );
      Console::WriteLine( "-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal );
   }

   Console::WriteLine( "Custom Attributes for Method 'HelloWorld()' in 'MyType':" );
   customAttrs = myType->GetMember( "HelloWorld" )[ 0 ]->GetCustomAttributes( true );
   System::Collections::IEnumerator^ myEnum2 = customAttrs->GetEnumerator();
   while ( myEnum2->MoveNext() )
   {
      Object^ customAttr = safe_cast<Object^>(myEnum2->Current);
      array<Object^>^temp4 = gcnew array<Object^>(0);
      attrVal = DateLastUpdated::typeid->InvokeMember( "DateUpdated", BindingFlags::GetProperty, nullptr, customAttr, temp4 );
      Console::WriteLine( "-- Attribute: [{0} = \"{1}\"]", customAttr, attrVal );
   }

   Console::WriteLine( "---" );
   array<Object^>^temp5 = gcnew array<Object^>(0);
   Console::WriteLine( myType->InvokeMember( "HelloWorld", BindingFlags::InvokeMethod, nullptr, myInstance, temp5 ) );
}

import System.*;
import System.Threading.*;
import System.Reflection.*;
import System.Reflection.Emit.*;

// We will apply this custom attribute to our dynamic type.
public class ClassCreator extends Attribute
{
    private String creator;

    /** @property 
     */
    public String get_Creator()
    {
        return creator ;
    } //get_Creator

    public ClassCreator(String name) 
    {
        this.creator = name;
    } //ClassCreator
} //ClassCreator

// We will apply this dynamic attribute to our dynamic method.
public class DateLastUpdated extends Attribute
{
    private String dateUpdated;
    /** @property 
     */
    public String get_DateUpdated()
    {
        return dateUpdated ;
    } //get_DateUpdated

    public DateLastUpdated(String theDate) 
    {
        this.dateUpdated = theDate;
    } //DateLastUpdated
} //DateLastUpdated

class MethodBuilderCustomAttributesDemo
{
    public static Type BuildTypeWithCustomAttributesOnMethod() 
    {
        AppDomain currentDomain = System.Threading.Thread.GetDomain();
        AssemblyName myAsmName = new AssemblyName();
        myAsmName.set_Name("MyAssembly");
        AssemblyBuilder myAsmBuilder = currentDomain.DefineDynamicAssembly(
            myAsmName, AssemblyBuilderAccess.Run);
        ModuleBuilder myModBuilder =
            myAsmBuilder.DefineDynamicModule("MyModule");
        // First, we'll build a type with a custom attribute attached.
        TypeBuilder myTypeBuilder = myModBuilder.DefineType(
            "MyType", TypeAttributes.Public);
        Type ctorParams[] = new Type[]{String.class.ToType()};
        ConstructorInfo classCtorInfo = 
            ClassCreator.class.ToType().GetConstructor(ctorParams);
        CustomAttributeBuilder myCABuilder =  
            new CustomAttributeBuilder(classCtorInfo,
            new Object[]{"Joe Programmer"});
        myTypeBuilder.SetCustomAttribute(myCABuilder);

        // Now, let's build a method and add a custom attribute to it.
        MethodBuilder myMethodBuilder = myTypeBuilder.DefineMethod(
            "HelloWorld", MethodAttributes.Public, null, new Type[]{});
        ctorParams = new Type[]{String.class.ToType()};
        classCtorInfo =
            DateLastUpdated.class.ToType().GetConstructor(ctorParams);
        CustomAttributeBuilder myCABuilder2 = new CustomAttributeBuilder(
            classCtorInfo, new Object[]{DateTime.get_Now().ToString()});
        myMethodBuilder.SetCustomAttribute(myCABuilder2);
        ILGenerator myIL = myMethodBuilder.GetILGenerator();
        myIL.EmitWriteLine("Hello, world!");
        myIL.Emit(OpCodes.Ret);      
        return myTypeBuilder.CreateType() ;
    } //BuildTypeWithCustomAttributesOnMethod

    public static void main(String[] args)
    {
        Type myType = BuildTypeWithCustomAttributesOnMethod();      
        Object myInstance = Activator.CreateInstance(myType);      
        Object customAttrs[] = myType.GetCustomAttributes(true);      
        Console.WriteLine("Custom Attributes for Type 'MyType':");      
        Object attrVal = null;
        for (int iCtr=0; iCtr < customAttrs.length; iCtr++) {
            Object customAttr = customAttrs[iCtr];
            attrVal = ClassCreator.class.ToType().InvokeMember
                ("Creator", BindingFlags.GetProperty, null, customAttr,
                new Object[] {});
            Console.WriteLine(
                "-- Attribute: [{0} = \"{1}\"]", customAttr,attrVal);
        }      
        Console.WriteLine(
            "Custom Attributes for Method 'HelloWorld()' in 'MyType':");      
        customAttrs =
            myType.GetMember("HelloWorld")[0].GetCustomAttributes(true);
        for(int iCtr = 0; iCtr < customAttrs.length; iCtr++) {
            Object customAttr = customAttrs[iCtr];
            attrVal = DateLastUpdated.class.ToType().InvokeMember(
                "DateUpdated", BindingFlags.GetProperty, null, 
                customAttr, new Object[] {});
            Console.WriteLine(
                "-- Attribute: [{0} = \"{1}\"]",customAttr, attrVal);
        }      
        Console.WriteLine("---");      
        Console.WriteLine(myType.InvokeMember(
            "HelloWorld", BindingFlags.InvokeMethod, null, 
            myInstance, new Object[] {}));
    } //main
} //MethodBuilderCustomAttributesDemo

继承层次结构

System.Object
System.Reflection.Emit.CustomAttributeBuilder

线程安全

此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。

平台

Windows 98、Windows 2000 SP4、Windows Millennium Edition、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

通过

CustomAttributeBuilder 类

语法

备注

示例

继承层次结构

线程安全

平台

版本信息

.NET Framework

请参见

参考

其他资源