public double?GetOrderTotalPrice(List <Item> orderedItemList, int paymentMethodId, int deliveryTypeId) { double?totalPrice = 0; foreach (var item in orderedItemList) { double?itemPrice = item.Quantity * item.Product.Price; totalPrice += itemPrice; } ; totalPrice += _paymentMethodService.GetCost(paymentMethodId); totalPrice += _deliveryTypeService.GetCost(deliveryTypeId); return(totalPrice); }