DoWorkEventArgs.Argument Property

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;
    }
}