public Model(ViewModel xViewModel)
 {
     _ViewModel = xViewModel;
     DispatcherTimer lTimer = new DispatcherTimer();
     lTimer.Interval = new TimeSpan(0, 0, 3);
     lTimer.Tick += new EventHandler(Timer_Tick);
     lTimer.Start();
 } // constructor
        } // constructor

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            ViewModel lViewModel = new ViewModel(myChart);
            DataContext = lViewModel;
            _Model = new Model(lViewModel);
        } //