wpf中防止界面卡死的写法

 this.button1.Content = "正在计算";
            Action action = new Action(() => {
                System.Threading.Thread.Sleep(3000);
                this.Dispatcher.BeginInvoke(new Action(() =>
                {
                    this.button1.Content = "计算完毕";
                }), System.Windows.Threading.DispatcherPriority.SystemIdle, null);
            });
            action.BeginInvoke(null,null);