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Enum.IsDefined Method

Returns an indication whether a constant with a specified value exists in a specified enumeration.

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

public static bool IsDefined (
	Type enumType,
	Object value
/** @attribute ComVisibleAttribute(true) */ 
public static boolean IsDefined (
	Type enumType, 
	Object value
public static function IsDefined (
	enumType : Type, 
	value : Object
) : boolean



An enumeration type.


The value or name of a constant in enumType.

Return Value

true if a constant in enumType has a value equal to value; otherwise, false.

Exception typeCondition


enumType or value is a null reference (Nothing in Visual Basic).


enumType is not an Enum.


The type of value is not an enumType.


The type of value is not an underlying type of enumType.


value is not type SByte, Int16, Int32, Int64, Byte, UInt16, UInt32, or UInt64, or String.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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