Export (0) Print
Expand All
Expand Minimize

AsyncCompletedEventHandler Delegate

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

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

[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public delegate void AsyncCompletedEventHandler(
	Object sender,
	AsyncCompletedEventArgs e
)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.ComponentModel.AsyncCompletedEventArgs

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

NoteNote:

The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes.

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 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0

.NET Compact Framework

Supported in: 3.5

XNA Framework

Supported in: 3.0, 2.0, 1.0

Community Additions

ADD
Show:
© 2014 Microsoft