Zatrzymanie background workera

            worker = new BackgroundWorker();
            worker.DoWork += delegate
            {
                for (int i = 3; i > 0; i--)
                {
                    this.Dispatcher.Invoke((Action)(() => { button1.Content = Convert.ToString(i); }));
                    System.Threading.Thread.Sleep(1000);
                    
                }
            };
            worker.RunWorkerCompleted += delegate { Button_Click_1(); };
            worker.RunWorkerAsync();

worker.CancelAsync();

A first chance exception of type 'System.InvalidOperationException' occurred in System.dll

Additional information: Proces BackgroundWorker nie obsługuje anulowania. Zmodyfikuj stan procesu WorkerSupportsCancellation, tak aby proces obsługiwał anulowanie.