public MainViewModel()
{
//os = new OrderSystem();
//os.StartWorkDay();
systemController = new SystemController();
systemController.onProcess = new Action <string>(receiveMessage);
this._dispatcher = Dispatcher.CurrentDispatcher;
systemController.RequestListOfBurgers();
this.ListViewBurgers = systemController.GetListViewBurger();
this.AddToCartCommand = new RelayCommand(param => AddToCart(), null);
this.DeleteFromCartCommand = new RelayCommand(param => DeleteFromCart(), null);
this.OrderBurgerCommand = new RelayCommand(param => OrderBurger(), null);
this.SubscribeCommand = new RelayCommand(param => Subscribe(), null);
}