RunWorkerCompletedEventArgs
Class
Definition
Provides data for the MethodNameCompleted event.
public class RunWorkerCompletedEventArgs : System.ComponentModel.AsyncCompletedEventArgs
- Inheritance
Inherited Members
System.ComponentModel.AsyncCompletedEventArgs
System.EventArgs
System.Object
Examples
The following code example illustrates the use of RunWorkerCompletedEventArgs. This example is part of a larger sample for the BackgroundWorker class.
// This event handler deals with the results of the
// background operation.
void backgroundWorker1_RunWorkerCompleted( Object^ /*sender*/, RunWorkerCompletedEventArgs^ e )
{
// First, handle the case where an exception was thrown.
if ( e->Error != nullptr )
{
MessageBox::Show( e->Error->Message );
}
else
if ( e->Cancelled )
{
// Next, handle the case where the user cancelled
// the operation.
// Note that due to a race condition in
// the DoWork event handler, the Cancelled
// flag may not have been set, even though
// CancelAsync was called.
resultLabel->Text = "Cancelled";
}
else
{
// Finally, handle the case where the operation
// succeeded.
resultLabel->Text = e->Result->ToString();
}
// Enable the UpDown control.
this->numericUpDown1->Enabled = true;
// Enable the Start button.
startAsyncButton->Enabled = true;
// Disable the Cancel button.
cancelAsyncButton->Enabled = false;
}
// This event handler deals with the results of the
// background operation.
private void backgroundWorker1_RunWorkerCompleted(
object sender, RunWorkerCompletedEventArgs e)
{
// First, handle the case where an exception was thrown.
if (e.Error != null)
{
MessageBox.Show(e.Error.Message);
}
else if (e.Cancelled)
{
// Next, handle the case where the user canceled
// the operation.
// Note that due to a race condition in
// the DoWork event handler, the Cancelled
// flag may not have been set, even though
// CancelAsync was called.
resultLabel.Text = "Canceled";
}
else
{
// Finally, handle the case where the operation
// succeeded.
resultLabel.Text = e.Result.ToString();
}
// Enable the UpDown control.
this.numericUpDown1.Enabled = true;
// Enable the Start button.
startAsyncButton.Enabled = true;
// Disable the Cancel button.
cancelAsyncButton.Enabled = false;
}
' This event handler deals with the results of the
' background operation.
Private Sub backgroundWorker1_RunWorkerCompleted( _
ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs) _
Handles backgroundWorker1.RunWorkerCompleted
' First, handle the case where an exception was thrown.
If (e.Error IsNot Nothing) Then
MessageBox.Show(e.Error.Message)
ElseIf e.Cancelled Then
' Next, handle the case where the user canceled the
' operation.
' Note that due to a race condition in
' the DoWork event handler, the Cancelled
' flag may not have been set, even though
' CancelAsync was called.
resultLabel.Text = "Canceled"
Else
' Finally, handle the case where the operation succeeded.
resultLabel.Text = e.Result.ToString()
End If
' Enable the UpDown control.
Me.numericUpDown1.Enabled = True
' Enable the Start button.
startAsyncButton.Enabled = True
' Disable the Cancel button.
cancelAsyncButton.Enabled = False
End Sub 'backgroundWorker1_RunWorkerCompleted
Remarks
If you are using a class that implements the Event-based Asynchronous Pattern Overview, the class provides a MethodNameCompleted event. MethodName is a placeholder for the first part of the method's name. BackgroundWorker.OnRunWorkerCompleted is an example of the name of such a method. If you add an instance of the RunWorkerCompletedEventArgs delegate to the event, you will receive information about the outcome of asynchronous operations in the RunWorkerCompletedEventArgs parameter of the corresponding event handler.
Note
The HostProtectionAttribute attribute applied to this class 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.
Constructors
| RunWorkerCompletedEventArgs(Object, Exception, Boolean) |
Initializes a new instance of the RunWorkerCompletedEventArgs class. |
Properties
| Result |
Gets a value that represents the result of an asynchronous operation. |
| UserState |
Gets a value that represents the user state. |