IAsyncResult.AsyncWaitHandle Property

Gets a WaitHandle that is used to wait for an asynchronous operation to complete.

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

WaitHandle AsyncWaitHandle { get; }
/** @property */
WaitHandle get_AsyncWaitHandle ()

function get AsyncWaitHandle () : WaitHandle

Not applicable.

Property Value

A WaitHandle that is used to wait for an asynchronous operation to complete.

The return value allows the client to wait for an asynchronous operation to complete instead of polling IsCompleted until the operation concludes. The return value can be used to perform a WaitOne, WaitAny, or WaitAll operation.

The common language runtime supplies a number of waitable objects, such as ManualResetEvent, AutoResetEvent, and Mutex, all of which mirror Win32 synchronization primitives.

Notes to Implementers: The object that implements IAsyncResult does not need to create the WaitHandle until the AsyncWaitHandle property is read. It is the choice of the IAsyncResult implementer. However, if the implementer creates AsyncWaitHandle, it is the responsibility of the implementer to signal the WaitHandle that will terminate the wait at the appropriate time. For example, System.Runtime.Remoting.Messaging.AsyncResult terminates the wait on behalf of the caller when an asynchronously invoked method returns. Once created, AsyncWaitHandle should be kept alive until the user calls the method that concludes the asynchronous operation. At that time the object behind AsyncWaitHandle can be discarded.

Notes to Callers: Clients that wait for the operation to complete (as opposed to polling) use this property to obtain a synchronization object to wait on.

Windows 98, Windows Server 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 Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0