Represents the method that will handle the DoWork event. This class cannot be inherited.
(in System.dll)
Visual Basic (Declaration)
<HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _
Public Delegate Sub DoWorkEventHandler ( _
sender As Object, _
e As DoWorkEventArgs _
)
Dim instance As New DoWorkEventHandler(AddressOf HandlerMethod)
[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public delegate void DoWorkEventHandler(
Object sender,
DoWorkEventArgs e
)
[HostProtectionAttribute(SecurityAction::LinkDemand, SharedState = true)]
public delegate void DoWorkEventHandler(
Object^ sender,
DoWorkEventArgs^ e
)
JScript does not support delegates.
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 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 Sub backgroundWorker1_DoWork( _
sender As Object, e As DoWorkEventArgs) _
Handles backgroundWorker1.DoWork
' Do not access the form's BackgroundWorker reference directly.
' Instead, use the reference provided by the sender parameter.
Dim bw As BackgroundWorker = CType( sender, BackgroundWorker )
' Extract the argument.
Dim arg As Integer = Fix(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 Then
e.Cancel = True
End If
End Sub
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;
}
}
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
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
Reference
Other Resources