DateTime lastClick = DateTime.Now;  object obj = new object();  int i = 0;  private void Button_Click(object sender, RoutedEventArgs e)  {   this.IsEnabled = false;     var t = (DateTime.Now - lastClick).TotalMilliseconds;   i++;   lastClick = DateTime.Now;   System.Diagnostics.Debug.Print(t + "," + i + ";" + DateTime.Now);   Thread.Sleep(2000);      this.IsEnabled = true;  }

private void Button_Click(object sender, RoutedEventArgs e)  {   this.IsEnabled = false;   DispatcherHelper.DoEvents();   var t = (DateTime.Now - lastClick).TotalMilliseconds;   i++;   lastClick = DateTime.Now;   System.Diagnostics.Debug.Print(t + "," + i + ";" + DateTime.Now);   Thread.Sleep(2000);      this.IsEnabled = true;  }  public static class DispatcherHelper  {   [SecurityPermissionAttribute(SecurityAction.Demand, Flags = SecurityPermissionFlag.UnmanagedCode)]   public static void DoEvents()   {    DispatcherFrame frame = new DispatcherFrame();    Dispatcher.CurrentDispatcher.BeginInvoke(DispatcherPriority.Background, new DispatcherOperationCallback(ExitFrames), frame);    try { Dispatcher.PushFrame(frame); }    catch (InvalidOperationException) { }   }   private static object ExitFrames(object frame)   {    ((DispatcherFrame)frame).Continue = false;    return null;   }  }