IAsyncResult Interface

 

Represents the status of an asynchronous operation.

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

[<ComVisibleAttribute(true)>]
type IAsyncResult = interface end

NameDescription
System_CAPS_pubpropertyAsyncState

Gets a user-defined object that qualifies or contains information about an asynchronous operation.

System_CAPS_pubpropertyAsyncWaitHandle

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

System_CAPS_pubpropertyCompletedSynchronously

Gets a value that indicates whether the asynchronous operation completed synchronously.

System_CAPS_pubpropertyIsCompleted

Gets a value that indicates whether the asynchronous operation has completed.

The IAsyncResult 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. IAsyncResult objects are also passed to methods invoked by AsyncCallback delegates when an asynchronous operation completes.

An object that supports the IAsyncResult interface stores state information for an asynchronous operation and provides a synchronization object to allow threads to be signaled when the operation completes.

System_CAPS_noteNote

The AsyncResult class is the implementation of IAsyncResult that is returned by the BeginInvoke method when you use a delegate to call a method asynchronously.

For a detailed description of how the IAsyncResult 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.

No code example is currently available or this language may not be supported.
No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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