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Attribute::IsDefined Method (Module, Type)

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

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

static bool IsDefined(
	Module^ element, 
	Type^ attributeType


Type: System.Reflection::Module
An object derived from the Module class that describes a portable executable file.
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.


element or attributeType is nullptr.


attributeType is not derived from Attribute.

The ancestors of element are not searched for custom attributes.

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

using namespace System;
using namespace System::Diagnostics;

// Add the Debuggable attribute to the module.
namespace IsDef2CS
   ref class DemoClass
      static void Main()

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

         // See if the Debuggable attribute is defined for this module.
         bool isDef = Attribute::IsDefined( clsType->Module, DebuggableAttribute::typeid );

         // Display the result.
         Console::WriteLine( "The Debuggable attribute {0} "
         "defined for Module {1}.", isDef ? (String^)"is" : "is not", clsType->Module->Name );

         // If the attribute is defined, display the JIT settings.
         if ( isDef )

            // Retrieve the attribute itself.
            DebuggableAttribute^ dbgAttr = dynamic_cast<DebuggableAttribute^>(Attribute::GetCustomAttribute( clsType->Module, DebuggableAttribute::typeid ));
            if ( dbgAttr != nullptr )
               Console::WriteLine( "JITTrackingEnabled is {0}.", dbgAttr->IsJITTrackingEnabled );
               Console::WriteLine( "JITOptimizerDisabled is {0}.", dbgAttr->IsJITOptimizerDisabled );
                        Console::WriteLine( "The Debuggable attribute "
            "could not be retrieved." );



 * Output:
 * The Debuggable attribute is defined for Module IsDef2CS.exe.
 * JITTrackingEnabled is True.
 * JITOptimizerDisabled is False.

.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.