public MainWindow()
        {
            InitializeComponent();

            options op = new options();

            this.mainframe.NavigationService.Navigate(op);


            //  time

            DispatcherTimer timer = new DispatcherTimer();

            timer.Interval = TimeSpan.FromSeconds(1);
            timer.Tick    += timer_Tick;
            timer.Start();
        }
        private void back_Click(object sender, RoutedEventArgs e)
        {
            options o = new options();

            this.NavigationService.Navigate(o);
        }