namespace WpfApplication1 { /// <summary> /// Interaction logic for Window1.xaml /// </summary> public partial class Window1 : Window { BackgroundWorker bgWorker; Action<int> myProgressReporter; public Window1() { InitializeComponent(); bgWorker = new BackgroundWorker(); bgWorker.DoWork += bgWorker_Task; bgWorker.RunWorkerCompleted += myWorker_RunWorkerCompleted; // hook event to method bgWorker.ProgressChanged += bgWorker_ReportProgress; // hook the delegate to the method myProgressReporter = updateProgress; bgWorker.WorkerReportsProgress = true; } private void myWorker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e) { object result; result = e.Result; MessageBox.Show(result.ToString()); progressBar1.Value = 0; button1.IsEnabled = true; } private void bgWorker_ReportProgress(object sender, ProgressChangedEventArgs e) { System.Windows.Threading.Dispatcher disp = button1.Dispatcher; disp.BeginInvoke(myProgressReporter,e.ProgressPercentage); //Dispatcher.BeginInvoke(myProgressReporter, DispatcherPriority.Normal, e.ProgressPercentage); } private void updateProgress(int progressPercentage) { progressBar1.Value = progressPercentage; } private void bgWorker_Task(Object sender, DoWorkEventArgs e) { int total = 1000; for (int i = 1; i <= total; i++) { if (bgWorker.WorkerReportsProgress) { int p = (int)(((float)i / (float)total) * 100); bgWorker.ReportProgress(p); } Thread.Sleep(1); // Without Thread.Sleep(x) the main thread freezes or gives stackoverflow exception, } e.Result = "Completed"; } private void button1_Click(object sender, RoutedEventArgs e) { if(!bgWorker.IsBusy) bgWorker.RunWorkerAsync("This is a background process"); button1.IsEnabled = false; } } }