public void MakeOrder(List <OrderItemData> orderItemDatas) { var order = new Order(); var orderItems = new List <OrderItem>(); foreach (var item in orderItemDatas) { var clothes = AddClothes(item.Type, item.Price, item.Size, item.Color, item.Amount); orderItems.Add(new OrderItem { Amount = item.Amount, OrderItemId = Guid.NewGuid().ToString(), Clothes = clothes }); } order.OrderItems = orderItems; order.SupplierId = orderItemDatas.FirstOrDefault().SupplierId; DbContext.AddOrder(order); }