private void quit_Click(object sender, RoutedEventArgs e)
        {
            MessageBoxResult key =MessageBox.Show("确定退出？","温馨提示",MessageBoxButton.YesNo,MessageBoxImage.Question,MessageBoxResult.No);
            if (key == MessageBoxResult.Yes)
            {
               // MessageBox.Show("YES");
                System.Environment.Exit(0);
               
            }
            else if (key == MessageBoxResult.No)
            {
                MessageBox.Show("NO");
            }
           
        }

这个方法有很多种，大家可以把自己的方法贴上来