Returns an indication whether a constant with a specified value exists in a specified enumeration.
Assembly: mscorlib (in mscorlib.dll)
[<ComVisibleAttribute(true)>] static member IsDefined : enumType:Type * value:Object -> bool
- Type: System.Type
An enumeration type.
- Type: System.Object
The value or name of a constant in enumType.
Return ValueType: System.Boolean
true if a constant in enumType has a value equal to value; otherwise, false.
enumType or value is a null reference (Nothing in Visual Basic).
enumType is not an Enum.
The type of value is an enumeration, but it is not an enumeration of type enumType.
The type of value is not an underlying type of enumType.
The value parameter can be any of the following:
Any member of type enumType.
A variable whose value is an enumeration member of type enumType.
The string representation of the name of an enumeration member. The characters in the string must have the same case as the enumeration member name.
A value of the underlying type of enumType.
If the constants in enumType define a set of bit fields and value contains the values, names, or underlying values of multiple bit fields, the method returns false. In other words, for enumerations that define a set of bit fields, the method determines only whether a single bit field belongs to the enumeration. To determine whether multiple bit fields are set in an enumeration type that is tagged with the FlagsAttribute attribute, you can call the HasFlag method.Notes to Callers
If enumType is an enumeration that is defined by using the FlagsAttribute attribute, the method returns false if multiple bit fields in value are set but value does not correspond to a composite enumeration value, or if value is a string concatenation of the names of multiple bit flags. In the following example, a Pets enumeration is defined with the FlagsAttribute attribute. The method returns false when you pass it an enumeration value that has two bit fields (Pets.Dog and Pets.Cat) set, and when you pass it the string representation of that enumeration value ("Dog, Cat").
You can determine whether multiple bit fields are set by calling the HasFlag method.
The following example defines an enumeration named PetType that consists of individual bit fields. It then calls the method with possible underlying enumeration values, string names, and composite values that result from setting multiple bit fields.
.NET FrameworkSupported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.