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Attribute::IsDefined Method (MemberInfo, Type)

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

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

public:
static bool IsDefined(
	MemberInfo^ element, 
	Type^ attributeType
)

Parameters

element
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.
attributeType
Type: System::Type
The type, or a base type, of the custom attribute to search for.

Return Value

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

ExceptionCondition
ArgumentNullException

element or attributeType is nullptr.

ArgumentException

attributeType is not derived from Attribute.

NotSupportedException

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

The ancestors of element are searched for custom attributes.

NoteNote

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
   {
   public:

      // Assign the Obsolete attribute to a method.

      [Obsolete("This method is obsolete.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

      void Method2(){}

   };

   ref class DemoClass
   {
   public:
      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 );
            else
                        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.

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