RunWorkerCompletedEventArgs Class

// 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;
}