Cancels a pending asynchronous operation.
Assembly: System.ServiceModel.Discovery (in System.ServiceModel.Discovery.dll)
An ArgumentNullException is thrown if userState is null. If multiple or operations are called with the same userState value, and is called with that userState value, an is thrown,
- Full trust for the immediate caller. This member cannot be used by partially trusted code. For more information, see Using Libraries from Partially Trusted Code.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, 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.