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MemberInfo.IsDefined メソッド

派生クラスによってオーバーライドされた場合、このメンバに attributeType のインスタンスが 1 つ以上定義されているかどうかを示します。

Public MustOverride Function IsDefined( _
   ByVal attributeType As Type, _   ByVal inherit As Boolean _) As Boolean Implements ICustomAttributeProvider.IsDefined
[C#]
public abstract bool IsDefined(TypeattributeType,boolinherit);
[C++]
public: virtual bool IsDefined(Type* attributeType,boolinherit) = 0;
[JScript]
public abstract function IsDefined(
   attributeType : Type,inherit : Boolean) : Boolean;

パラメータ

  • attributeType
    カスタム属性を適用する対象の Type オブジェクト。
  • inherit
    このメンバの継承チェインを検索して属性を見つけるかどうかを指定します。

戻り値

このメンバに attributeType のインスタンスが 1 つ以上定義されている場合は true 。それ以外の場合は false

実装

ICustomAttributeProvider.IsDefined

使用例

[Visual Basic, C#, C++] 指定した属性が指定したメンバで定義されているかどうかを調べる例を次に示します。

 
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

[C#] 

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);
        }
    }
}

[C++] 

#using <mscorlib.dll>

using namespace System;
using namespace System::Reflection;

// Define a custom attribute with one named parameter.
[AttributeUsage(AttributeTargets::All)]
public __gc class MyAttribute : public Attribute
{
private:
   String* myName;
public:
   MyAttribute(String* name)
   {
      myName = name;
   }
   __property String* get_Name()
   {
      return myName;
   }
};

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

int 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(S"\nThe attributes of type MyAttribute for the member {0} are: \n",
               myMembers->Item[i]);
            for (int j = 0; j < myAttributes->Length; j++)
               // Display the value associated with the attribute.
               Console::WriteLine(S"The value of the attribute is : \"{0}\"",
               (__try_cast<MyAttribute*>(myAttributes[j]))->Name);
         }
      }
   } catch (Exception* e) {
      Console::WriteLine(S"An exception occurred: {0}", e->Message);
   }
}

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必要条件

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET

参照

MemberInfo クラス | MemberInfo メンバ | System.Reflection 名前空間