public OrderErrorCodes AddToOrder(int dishNumber, int tableNumber) { var dish = dishManager.GetDishByDishNumber(dishNumber); if (dish == null) { return(OrderErrorCodes.NoSuchDish); } var table = tableManager.GetTableByTableNumber(tableNumber); if (table == null) { return(OrderErrorCodes.NoSuchTable); } var order = orderManager.GetActiveOrder(table.TableID); if (order == null) { order = orderManager.CreateActiveOrder(table.TableID); } orderManager.AddToOrder(order.OrderID, dish.DishID); return(OrderErrorCodes.Ok); }