Indicates that the default value for the attributed field or parameter is an instance of System.Runtime.InteropServices.UnknownWrapper, where the System.Runtime.InteropServices.UnknownWrapper.WrappedObject is null. This class cannot be inherited.
See Also: IUnknownConstantAttribute Members
Syntax
[System.AttributeUsage(System.AttributeTargets.Field | System.AttributeTargets.Parameter | System.AttributeTargets.All, Inherited=false)]
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class IUnknownConstantAttribute : CustomConstantAttribute
[System.Runtime.InteropServices.ComVisible(true)]
public sealed class IUnknownConstantAttribute : CustomConstantAttribute
Remarks
You can apply this attribute to fields or parameters.
The type library importer uses this attribute to distinguish a default value of type VT_UNKNOWN from null.
For more information about constant attributes, see the System.Runtime.CompilerServices.CustomConstantAttribute class.
The classes in System.Runtime.CompilerServices are for compiler writers use only.
Requirements
Namespace: System.Runtime.CompilerServices
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0