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Attribute::IsDefined Method (MemberInfo, Type, Boolean)

Determines whether any custom attributes are applied to a member of a type. Parameters specify the member, the type of the custom attribute to search for, and whether to search ancestors of the member.

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

static bool IsDefined(
	MemberInfo^ element, 
	Type^ attributeType, 
	bool inherit


Type: System.Reflection::MemberInfo
An object derived from the MemberInfo class that describes a constructor, event, field, method, type, or property member of a class.
Type: System::Type
The type, or a base type, of the custom attribute to search for.
Type: System::Boolean
If true, specifies to also search the ancestors of element for custom attributes.

Return Value

Type: System::Boolean
true if a custom attribute of type attributeType is applied to element; otherwise, false.


element or attributeType is nullptr.


attributeType is not derived from Attribute.


element is not a constructor, method, property, event, type, or field.


Starting with the .NET Framework version 2.0, this method returns true if a type, method, or constructor has security attributes stored in the new metadata format. Assemblies compiled with version 2.0 or later use the new format. Dynamic assemblies and assemblies compiled with earlier versions of the .NET Framework use the old XML format. See Emitting Declarative Security Attributes.

The following code example illustrates the use of IsDefined, taking a MemberInfo as a parameter.

using namespace System;
using namespace System::Reflection;

namespace IsDef4CS
   public ref class TestClass

      // Assign the Obsolete attribute to a method.

      [Obsolete("This method is obsolete. Use Method2 instead.")]
      void Method1(){}

      void Method2(){}


   ref class DemoClass
      static void Main()

         // Get the class type to access its metadata.
         Type^ clsType = TestClass::typeid;

         // Get the MethodInfo object for Method1.
         MethodInfo^ mInfo = clsType->GetMethod( "Method1" );

         // See if the Obsolete attribute is defined for this method.
         bool isDef = Attribute::IsDefined( mInfo, ObsoleteAttribute::typeid );

         // Display the result.
         Console::WriteLine( "The Obsolete Attribute {0} defined for {1} of class {2}.", isDef ? (String^)"is" : "is not", mInfo->Name, clsType->Name );

         // If it's defined, display the attribute's message.
         if ( isDef )
            ObsoleteAttribute^ obsAttr = dynamic_cast<ObsoleteAttribute^>(Attribute::GetCustomAttribute( mInfo, ObsoleteAttribute::typeid ));
            if ( obsAttr != nullptr )
                        Console::WriteLine( "The message is: \"{0}\".", obsAttr->Message );
                        Console::WriteLine( "The message could not be retrieved." );



 * Output:
 * The Obsolete Attribute is defined for Method1 of class TestClass.
 * The message is: "This method is obsolete. Use Method2 instead.".

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.