DoWorkEventHandler Delegate
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DoWorkEventHandler Delegate


Represents the method that will handle the DoWork event. This class cannot be inherited.

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

[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public delegate void DoWorkEventHandler(
	object sender,
	DoWorkEventArgs e


Type: System.Object

The source of the event.

Type: System.ComponentModel.DoWorkEventArgs

A DoWorkEventArgs that contains the event data.

When you create a DoWorkEventHandler 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 NIB: Events and Delegates.

The following code example demonstrates how to use the DoWorkEventHandler delegate to handle the DoWork event. For a full code listing, see How to: Run an Operation in the Background.

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    // Do not access the form's BackgroundWorker reference directly.
    // Instead, use the reference provided by the sender parameter.
    BackgroundWorker bw = sender as BackgroundWorker;

    // Extract the argument.
    int arg = (int)e.Argument;

    // Start the time-consuming operation.
    e.Result = TimeConsumingOperation(bw, arg);

    // If the operation was canceled by the user, 
    // set the DoWorkEventArgs.Cancel property to true.
    if (bw.CancellationPending)
        e.Cancel = true;

Universal Windows Platform
Available since 10
.NET Framework
Available since 2.0
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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