public MainWindow()

        {

            InitializeComponent();

            DispatcherTimer timer = new DispatcherTimer();

            timer.Interval = TimeSpan.FromMilliseconds();

            timer.Tick += MyEventHandler;

            timer.Start();

        }

        public void MyEventHandler(object sender, EventArgs e)

        {

            tbxTime.Text = DateTime.Now.ToString("yyyy/MM/dd HH:m:ss");

        }