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TypeDelegator.IsDefined Method

Indicates whether a custom attribute identified by attributeType is defined.

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

abstract IsDefined : 
        attributeType:Type * 
        inherit:bool -> bool 
override IsDefined : 
        attributeType:Type * 
        inherit:bool -> bool 


Type: System.Type
Specifies whether to search this type's inheritance chain to find the attributes.
Type: System.Boolean
An array of custom attributes identified by type.

Return Value

Type: System.Boolean
true if a custom attribute identified by attributeType is defined; otherwise, false.


ICustomAttributeProvider.IsDefined(Type, Boolean)
_MemberInfo.IsDefined(Type, Boolean)


attributeType is a null reference (Nothing in Visual Basic).


The custom attribute type cannot be loaded.

.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

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.