ParameterInfo.IsDefined(Type, Boolean) Метод

Определение

Пространство имен:

System.Reflection

Сборка:

System.Runtime.dll

Исходный код:

ParameterInfo.cs

Определяет, применяется ли настраиваемый атрибут заданного типа или его производных типов к данному параметру.

public:
 virtual bool IsDefined(Type ^ attributeType, bool inherit);

public virtual bool IsDefined (Type attributeType, bool inherit);

abstract member IsDefined : Type * bool -> bool
override this.IsDefined : Type * bool -> bool

Public Overridable Function IsDefined (attributeType As Type, inherit As Boolean) As Boolean

Параметры

attributeType

Type

Объект Type, который требуется найти.

inherit

Boolean

Данный аргумент не учитывается для объектов этого типа.

Возвращаемое значение

Boolean

Значение true, если к этому параметру применяется один или несколько экземпляров типа attributeType или его производных типов; в противном случае — значение false.

Реализации

IsDefined(Type, Boolean)

Исключения

ArgumentNullException

attributeType имеет значение null.

ArgumentException

Параметр attributeType не является объектом типа Type, предоставленным средой CLR.

Примеры

В следующем примере определяются два настраиваемых атрибута: MyAttribute и MyDerivedAttribute. Класс MyDerivedAttribute является производным от MyAttribute. Затем в примере эти атрибуты применяются к параметрам метода класса примера.

При выполнении примера он использует IsDefined метод для проверки всех параметров всех методов в классе примера. Затем отображаются параметры, имеющие MyAttribute или MyDerivedAttribute.

// System::Reflection::ParameterInfo::GetCustomAttributes(Type, bool)
// System::Reflection::ParameterInfo::IsDefined(Type, bool)
using namespace System;
using namespace System::Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets::Parameter)]
public ref class MyAttribute: public Attribute
{
private:
   String^ myName;

public:
   MyAttribute( String^ name )
   {
      myName = name;
   }

   property String^ Name 
   {
      String^ get()
      {
         return myName;
      }
   }
};

// Derive another custom attribute from MyAttribute.
[AttributeUsage(AttributeTargets::Parameter)]
public ref class MyDerivedAttribute: public MyAttribute
{
public:
   MyDerivedAttribute( String^ name ) : MyAttribute( name ) {}
};

// Define a class with a method that has three parameters. Apply
// MyAttribute to one parameter, MyDerivedAttribute to another, and
// no attributes to the third. 
public ref class MyClass1
{
public:
   void MyMethod( [MyAttribute("This is an example parameter attribute")] 
                  int i,
                  [MyDerivedAttribute("This is another parameter attribute")] 
                  int j,
                  int k ){}
};

void main()
{
   // Get the type of the class 'MyClass1'.
   Type^ myType = MyClass1::typeid;

   // Get the members associated with the class 'MyClass1'.
   array<MethodInfo^>^myMethods = myType->GetMethods();

   // For each method of the class 'MyClass1', display all the parameters
   // to which MyAttribute or its derived types have been applied.
   for each ( MethodInfo^ mi in myMethods )
   {
      // Get the parameters for the method.
      array<ParameterInfo^>^ myParameters = mi->GetParameters();
      if ( myParameters->Length > 0 )
      {
         Console::WriteLine("\nThe following parameters of {0} have MyAttribute or a derived type:", mi);
         for each ( ParameterInfo^ pi in myParameters)
         {
            if (pi->IsDefined(MyAttribute::typeid, false))
            {
               Console::WriteLine("Parameter {0}, name = {1}, type = {2}", 
                  pi->Position, pi->Name, pi->ParameterType);
            }
         }
      }
   }
}

/* This code example produces the following output:

The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
Parameter 0, name = i, type = System.Int32
Parameter 1, name = j, type = System.Int32

The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:
 */

using System;
using System.Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets.Parameter)]
public class MyAttribute : Attribute
{
    private string myName;
    public MyAttribute(string name)
    {
        myName = name;
    }
    public string Name
    {
        get
        {
            return myName;
        }
    }
}

// Derive another custom attribute from MyAttribute
[AttributeUsage(AttributeTargets.Parameter)]
public class MyDerivedAttribute : MyAttribute
{
    public MyDerivedAttribute(string name) : base(name) {}
}

// Define a class with a method that has three parameters. Apply
// MyAttribute to one parameter, MyDerivedAttribute to another, and
// no attributes to the third.
public class MyClass1
{
    public void MyMethod(
        [MyAttribute("This is an example parameter attribute")]
        int i,
        [MyDerivedAttribute("This is another parameter attribute")]
        int j,
        int k )
    {
        return;
    }
}

public class MemberInfo_GetCustomAttributes
{
    public static void Main()
    {
        // Get the type of the class 'MyClass1'.
        Type myType = typeof(MyClass1);
        // Get the members associated with the class 'MyClass1'.
        MethodInfo[] myMethods = myType.GetMethods();

        // For each method of the class 'MyClass1', display all the parameters
        // to which MyAttribute or its derived types have been applied.
        foreach (MethodInfo mi in myMethods)
        {
            // Get the parameters for the method.
            ParameterInfo[] myParameters = mi.GetParameters();
            if (myParameters.Length > 0)
            {
                Console.WriteLine("\nThe following parameters of {0} have MyAttribute or a derived type: ", mi);
                foreach (ParameterInfo pi in myParameters)
                {
                    if (pi.IsDefined(typeof(MyAttribute), false))
                    {
                        Console.WriteLine("Parameter {0}, name = {1}, type = {2}",
                            pi.Position, pi.Name, pi.ParameterType);
                    }
                }
            }
        }
    }
}

/* This code example produces the following output:

The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
Parameter 0, name = i, type = System.Int32
Parameter 1, name = j, type = System.Int32

The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:
 */

Imports System.Reflection

' Define a custom attribute with one named parameter.
<AttributeUsage(AttributeTargets.Parameter)> _
Public Class MyAttribute
    Inherits Attribute
    Private myName As String

    Public Sub New(ByVal name As String)
        myName = name
    End Sub 

    Public ReadOnly Property Name() As String
        Get
            Return myName
        End Get
    End Property
End Class 

' Derive another custom attribute from MyAttribute
<AttributeUsage(AttributeTargets.Parameter)> _
Public Class MyDerivedAttribute
    Inherits MyAttribute

    Public Sub New(ByVal name As String)
        MyBase.New(name)
    End Sub 
End Class

' Define a class with a method that has three parameters. Apply
' MyAttribute to one parameter, MyDerivedAttribute to another, and
' no attributes to the third. 
Public Class MyClass1

    Public Sub MyMethod(<MyAttribute("This is an example parameter attribute")> _
                        ByVal i As Integer, _
                        <MyDerivedAttribute("This is another parameter attribute")> _
                        ByVal j As Integer, _
                        ByVal k As Integer)
        Return
    End Sub 
End Class 

Public Class MemberInfo_GetCustomAttributes

    Public Shared Sub Main()
        ' Get the type of the class 'MyClass1'.
        Dim myType As Type = GetType(MyClass1)
        ' Get the members associated with the class 'MyClass1'.
        Dim myMethods As MethodInfo() = myType.GetMethods()

        ' For each method of the class 'MyClass1', display all the parameters
        ' to which MyAttribute or its derived types have been applied.
        For Each mi As MethodInfo In myMethods
            ' Get the parameters for the method.
            Dim myParameters As ParameterInfo() = mi.GetParameters()
            If myParameters.Length > 0 Then
                Console.WriteLine(vbCrLf & "The following parameters of {0} have MyAttribute or a derived type: ", mi)
                For Each pi As ParameterInfo In myParameters
                    If pi.IsDefined(GetType(MyAttribute), False) Then
                        Console.WriteLine("Parameter {0}, name = {1}, type = {2}", _
                            pi.Position, pi.Name, pi.ParameterType)
                    End If
                Next
            End If
        Next
    End Sub 
End Class 

' This code example produces the following output:
'
'The following parameters of Void MyMethod(Int32, Int32, Int32) have MyAttribute or a derived type:
'Parameter 0, name = i, type = System.Int32
'Parameter 1, name = j, type = System.Int32
'
'The following parameters of Boolean Equals(System.Object) have MyAttribute or a derived type:

Комментарии

Этот метод игнорирует inherit параметр . Чтобы найти в цепочке наследования атрибуты параметров, используйте соответствующие перегрузки Attribute.IsDefined метода .