/// <summary> /// adds items to the order /// </summary> /// <param name="item"> the item being added</param> public void Add(IOrderItem item) { currentListIndex = orders.Count; parent.SendButt.IsEnabled = false; orders.Add(item); _subTotal += item.Price; _totalCalories += item.Calories; NotifyPropertyChanged("_subTotal"); NotifyPropertyChanged("_tax"); NotifyPropertyChanged("_total"); NotifyPropertyChanged("_totalCalories"); parent.swapScreens(); }