Represents the status of an asynchronous operation.
Assembly: mscorlib (in mscorlib.dll)
Thetype exposes the following members.
|AsyncState||Gets a user-defined object that qualifies or contains information about an asynchronous operation.|
|AsyncWaitHandle||Gets a WaitHandle that is used to wait for an asynchronous operation to complete.|
|CompletedSynchronously||Gets a value that indicates whether the asynchronous operation completed synchronously.|
|IsCompleted||Gets a value that indicates whether the asynchronous operation has completed.|
The interface is implemented by classes containing methods that can operate asynchronously. It is the return type of methods that initiate an asynchronous operation, such as FileStream.BeginRead, and it is passed to methods that conclude an asynchronous operation, such as FileStream.EndRead. objects are also passed to methods invoked by AsyncCallback delegates when an asynchronous operation completes.
An object that supports the interface stores state information for an asynchronous operation and provides a synchronization object to allow threads to be signaled when the operation completes.
The AsyncResult class is the implementation of that is returned by the BeginInvoke method when you use a delegate to call a method asynchronously.
For a detailed description of how the interface is used, see the Calling Synchronous Methods Asynchronously topic.
The following example demonstrates how to use the AsyncWaitHandle property to get a WaitHandle, and how to wait for an asynchronous call on a delegate. The WaitHandle is signaled when the asynchronous call completes, and you can wait for it by calling the WaitOne method.
The example consists of two classes: the class that contains the method that is called asynchronously, and the class that contains the Main method that makes the call.
For more information and more examples of calling methods asynchronously by using delegates, see Calling Synchronous Methods Asynchronously.
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.