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AsyncCompletedEventHandler Delegate

Represents the method that will handle the MethodNameCompleted event of an asynchronous operation.

Namespace: System.ComponentModel
Assembly: System (in system.dll)

public delegate void AsyncCompletedEventHandler (
	Object sender,
	AsyncCompletedEventArgs e
)
/** @delegate */
public delegate void AsyncCompletedEventHandler (
	Object sender, 
	AsyncCompletedEventArgs e
)
Not applicable.

Parameters

sender

The source of the event.

e

An System.ComponentModel.AsyncCompletedEventArgs that contains the event data.

When you create an AsyncCompletedEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event-handler method is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.

For an asynchronous method, called MethodName, in your component, you will have a corresponding MethodNameCompleted event, and an optional MethodNameCompletedEventArgs class.

For a component that supports multiple concurrent invocations of its asynchronous methods, the client can supply a unique token, or task ID, to distinguish which asynchronous task is raising particular events. The client's AsyncCompletedEventHandler can read the AsyncCompletedEventArgs.UserState property to determine which task is reporting completion. Your implementation should use the System.ComponentModel.AsyncOperationManager to create an System.ComponentModel.AsyncOperation that associates the client's task IDs with pending asynchronous tasks.

For a code example of the AsyncCompletedEventHandler delegate, see the example in the System.ComponentModel.AsyncCompletedEventArgs class.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, 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

XNA Framework

Supported in: 1.0

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