System.ComponentModel Names ...


.NET Framework Class Library
RunWorkerCompletedEventArgs Class

Provides data for the MethodNameCompleted event.

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

Visual Basic (Declaration)
<HostProtectionAttribute(SecurityAction.LinkDemand, SharedState := True)> _
Public Class RunWorkerCompletedEventArgs _
    Inherits AsyncCompletedEventArgs
Visual Basic (Usage)
Dim instance As RunWorkerCompletedEventArgs
C#
[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public class RunWorkerCompletedEventArgs : AsyncCompletedEventArgs
Visual C++
[HostProtectionAttribute(SecurityAction::LinkDemand, SharedState = true)]
public ref class RunWorkerCompletedEventArgs : public AsyncCompletedEventArgs
JScript
public class RunWorkerCompletedEventArgs extends AsyncCompletedEventArgs
Remarks

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.

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.

NoteNote:

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.

Examples

The following code example illustrates the use of RunWorkerCompletedEventArgs. This example is part of a larger sample for the BackgroundWorker class.

Visual Basic
' 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
C#
// 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;
}
Visual C++
// 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;
}
Inheritance Hierarchy

System..::.Object
  System..::.EventArgs
    System.ComponentModel..::.AsyncCompletedEventArgs
      System.ComponentModel..::.RunWorkerCompletedEventArgs
Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Platforms

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.
Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0
See Also

Reference

Other Resources

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Community Content

PrafulKapadia
Check for null before using e.Result.ToString()

I used the code above from RunWorkerCompleted in my own program. However, the program crashed. That is because the line

   resultLabel.Text = e.Result.ToString();

should include a check for null, like this:

   if (null != e.Result) resultLabel.Text = e.Result.ToString();
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