MemberInfo.IsDefined-Methode

Artikel
08/20/2007

Gibt beim Überschreiben in einer abgeleiteten Klasse an, ob eine oder mehrere Instanzen der attributeType-Eigenschaft auf diesen Member angewendet werden.

Namespace: System.Reflection
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
Public MustOverride Function IsDefined ( _
    attributeType As Type, _
    inherit As Boolean _
) As Boolean
'Usage
Dim instance As MemberInfo
Dim attributeType As Type
Dim inherit As Boolean
Dim returnValue As Boolean

returnValue = instance.IsDefined(attributeType, inherit)

public abstract bool IsDefined (
    Type attributeType,
    bool inherit
)

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

public abstract boolean IsDefined (
    Type attributeType, 
    boolean inherit
)

public abstract function IsDefined (
    attributeType : Type, 
    inherit : boolean
) : boolean

Parameter

attributeType
Das Type-Objekt, auf das die benutzerdefinierten Attribute angewendet werden.

inherit
Gibt an, ob beim Suchen der Attribute die Vererbungskette dieses Members durchsucht werden soll.

Rückgabewert

true, wenn eine oder mehrere Instanzen der attributeType-Eigenschaft auf diesen Member angewendet werden, andernfalls false.

Beispiel

Im folgenden Beispiel wird bestimmt, ob das angegebene Attribut auf den angegebenen Member angewendet wird.

Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic

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

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

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

' Define a class that has the custom attribute associated with one of its members.
Public Class MyClass1

    <MyAttribute("This is an example attribute.")> Public Sub MyMethod(ByVal i As Integer)
        Return
    End Sub 'MyMethod
End Class 'MyClass1

Public Class MemberInfo_GetCustomAttributes_IsDefined

    Public Shared Sub Main()
        Try
            ' Get the type of MyClass1.
            Dim myType As Type = GetType(MyClass1)
            ' Get the members associated with MyClass1.
            Dim myMembers As MemberInfo() = myType.GetMembers()

            ' Display the attributes for each of the members of MyClass1.
            Dim i As Integer
            For i = 0 To myMembers.Length - 1
                ' Display the attribute if it is of type MyAttribute.
                If myMembers(i).IsDefined(GetType(MyAttribute), False) Then
                    Dim myAttributes As [Object]() = myMembers(i).GetCustomAttributes(GetType(MyAttribute), False)
                    Console.WriteLine(ControlChars.Cr + "The attributes of type MyAttribute for the member {0} are: " + ControlChars.Cr, myMembers(i))
                    Dim j As Integer
                    For j = 0 To myAttributes.Length - 1
                        ' Display the value associated with the attribute.
                        Console.WriteLine("The value of the attribute is : ""{0}""", CType(myAttributes(j), MyAttribute).Name)
                    Next j
                End If
            Next i
        Catch e As Exception
            Console.WriteLine("An exception occurred: {0}", e.Message)
        End Try
    End Sub 'Main
End Class 'MemberInfo_GetCustomAttributes_IsDefined

using System;
using System.Reflection;

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

// Define a class that has the custom attribute associated with one of its members.
public class MyClass1
{
    [MyAttribute("This is an example attribute.")]
    public void MyMethod(int i)
    {
        return;
    }
}

public class MemberInfo_GetCustomAttributes_IsDefined
{
    public static void Main()
    {
        try
        {
            // Get the type of MyClass1.
            Type myType = typeof(MyClass1);
            // Get the members associated with MyClass1.
            MemberInfo[] myMembers = myType.GetMembers();

            // Display the attributes for each of the members of MyClass1.
            for(int i = 0; i < myMembers.Length; i++)
            {
                // Display the attribute if it is of type MyAttribute.
                if(myMembers[i].IsDefined(typeof(MyAttribute), false))
                {
                    Object[] myAttributes = myMembers[i].GetCustomAttributes(typeof(MyAttribute), false);
                    Console.WriteLine("\nThe attributes of type MyAttribute for the member {0} are: \n",
                        myMembers[i]);
                    for(int j = 0; j < myAttributes.Length; j++)
                        // Display the value associated with the attribute.
                        Console.WriteLine("The value of the attribute is : \"{0}\"",
                            ((MyAttribute)myAttributes[j]).Name);
                }
            }
        }
        catch(Exception e)
        {
            Console.WriteLine("An exception occurred: {0}", e.Message);
        }
    }
}

using namespace System;
using namespace System::Reflection;

// Define a custom attribute with one named parameter.

[AttributeUsage(AttributeTargets::All)]
public ref class MyAttribute: public Attribute
{
private:
   String^ myName;

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

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

// Define a class that has the custom attribute associated with one of its members.
public ref class MyClass1
{
public:

   [MyAttribute("This is an example attribute.")]
   void MyMethod( int i ){}
};

int main()
{
   try
   {
      // Get the type of MyClass1.
      Type^ myType = MyClass1::typeid;

      // Get the members associated with MyClass1.
      array<MemberInfo^>^myMembers = myType->GetMembers();

      // Display the attributes for each of the members of MyClass1.
      for ( int i = 0; i < myMembers->Length; i++ )
      {
         // Display the attribute if it is of type MyAttribute.
         if ( myMembers[ i ]->IsDefined( MyAttribute::typeid, false ) )
         {
            array<Object^>^myAttributes = myMembers[ i ]->GetCustomAttributes( MyAttribute::typeid, false );
            Console::WriteLine( "\nThe attributes of type MyAttribute for the member {0} are: \n", myMembers[ i ] );
            for ( int j = 0; j < myAttributes->Length; j++ )

               // Display the value associated with the attribute.
               Console::WriteLine( "The value of the attribute is : \"{0}\"",
                        (safe_cast<MyAttribute^>(myAttributes[ j ]))->Name );
         }
      }
   }
   catch ( Exception^ e ) 
   {
      Console::WriteLine( "An exception occurred: {0}", e->Message );
   }
}

import System.*;
import System.Reflection.*;

// Define a custom attribute with one named parameter.
/** @attribute AttributeUsage(AttributeTargets.All)
 */
public class MyAttribute extends Attribute
{
    private String myName;

    public MyAttribute(String name)
    {
        myName = name;
    } //MyAttribute

    /** @property 
     */
    public String get_Name()
    {
        return myName;
    } //get_Name
} //MyAttribute

// Define a class that has the custom attribute associated 
// with one of its members.
public class MyClass1
{
    /** @attribute MyAttribute("This is an example attribute.")
     */
    public void MyMethod(int i)
    {
        return;
    } //MyMethod
} //MyClass1

public class MemberInfo_GetCustomAttributes_IsDefined
{
    public static void main(String[] args)
    {
        try {
            // Get the type of MyClass1.
            Type myType = MyClass1.class.ToType();

            // Get the members associated with MyClass1.
            MemberInfo myMembers[] = myType.GetMembers();

            // Display the attributes for each of the members of MyClass1.
            for (int i = 0; i < myMembers.length; i++) {
                // Display the attribute if it is of type MyAttribute.
                if (((MemberInfo)myMembers.get_Item(i)).
                    IsDefined(MyAttribute.class.ToType(), false)) {
                    Object myAttributes[] = ((MemberInfo)myMembers.get_Item(i)).
                        GetCustomAttributes(MyAttribute.class.ToType(), false);
                    Console.WriteLine("\nThe attributes of type MyAttribute for"
                        + " the member {0} are: \n", myMembers.get_Item(i));

                    for (int j = 0; j < myAttributes.length; j++) {
                        // Display the value associated with the attribute.
                        Console.WriteLine("The value of the attribute is : \"" 
                            + "{0}\"", ((MyAttribute)myAttributes.get_Item(j)).
                            get_Name());
                    }
                }
            }
        }
        catch (System.Exception e) {
            Console.WriteLine("An exception occurred: {0}", e.get_Message());
        }
    } //main
} //MemberInfo_GetCustomAttributes_IsDefined

Plattformen

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile für Pocket PC, Windows Mobile für Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.

Freigeben über

MemberInfo.IsDefined-Methode

Syntax

Parameter

Rückgabewert

Beispiel

Plattformen

Versionsinformationen

.NET Framework

.NET Compact Framework

Siehe auch

Referenz

Zusätzliche Ressourcen