实体框架 6 的多重性为 1 或 0.1

在

模型绑定器创建模型、子项和孙项并使用上下文后，尝试将对象插入子集合时，我收到以下错误。保存更改((;

违反了多重性约束。关系"PPLib.Models.OrderDetail_OrderDetailPricelistProductOptions"的角色"OrderDetail_OrderDetailPricelistProductOptions_Source"具有多重性 1 或 0..1。

我的模型如下(为简洁起见，删除了属性(;

public class Order
{
    public int OrderId { get; set; }
    public virtual List<OrderDetail> OrderDetails { get; set; }
}
public class OrderDetail
{
    public int OrderDetailId { get; set; }
    public int OrderId { get; set; }
    public int ProductId { get; set; }
    public virtual Product Product { get; set; } //FK NAV
    public int? PricelistProductId { get; set; } // if a subscriber order ...has the ProductId from a PriceList.
    private decimal _Price = 0;
    public decimal Price  { get { return _Price; } set { _Price = value; } }
    private int _Quantity = 1;
    public int Quantity { get { return _Quantity; } set { _Quantity = value; } }
    public virtual List<OrderDetailPricelistProductOption> OrderDetailPricelistProductOptions { get; set; }
}
public class OrderDetailPricelistProductOption
{
    public int OrderDetailPricelistProductOptionId { get; set; }
    public int OrderDetailId { get; set; }
    public virtual List<OrderDetailPricelistProductOptionsDetail> OrderDetailPricelistProductOptionsDetails { get; set; }
}
public class OrderDetailPricelistProductOptionsDetail
{
    public int OrderDetailPricelistProductOptionsDetailId { get; set; }
    public int OrderDetailPricelistProductOptionId { get; set; }
    public string Name { get; set; }
}

更清楚的是：

如果我提交一个完整的新订单，其中包含订单详细信息列表、订单详细信息价格列表产品选项列表

和订单详细信息价格清单产品选项详细信息列表，则模型活页夹将完成其工作，并且我不会收到以下错误：

db.Orders.Add(order);
db.SaveChanges();

如果我提交"编辑"和"现有订单"，并提交"新建订单详细信息"列表、"订单详细信息价格列表产品选项"列表和"订单详细信息价格列表

产品选项详细信息"列表，则我从数据库上下文中获取订单，然后使用以下命令合并视图模型中的订单详细信息：

order.OrderDetails.AddRange(pricelistProductVM.Order.OrderDetails);

并且我在执行以下操作时没有收到任何错误：

db.Entry(order).State = EntityState.Modified;
db.SaveChanges();

我

有一个特殊的情况，我必须实例化一个名为autoFillOd的新OrderDetail，并从模型绑定器组装的现有OrderDetails之一注入其值。我更改了它的数量值，然后将其添加到 ViewModel 中的订单详细信息集合中，如下所示：

pricelistProductVM.Order.OrderDetails.Add(autoFillOd);

当我做数据库时。保存更改((，我收到错误。

您会注意到错误出在订单详细信息的子项上：OrderDetail_OrderDetailPricelistProductOptions_Source

为什么我不能将订单详细信息动态添加到订单详细信息集合中？所有订单详细信息都是新的(要插入(，因此副本之间的值相同，除了 Quantity 属性，它应该不是问题。

控制器操作如下：

[HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Add(pricelistProductVM pricelistProductVM)
    {
        OrderLogic ol = new OrderLogic();
        //Auth is running on execute
        int userId = WebSecurity.CurrentUserId;
        int websiteId = (int)Session["websiteId"];
        int? id = null; // mediaId
        int productId = pricelistProductVM.Product.ProductId;
        int? eventId = pricelistProductVM.eventId;
        string err = "";
        if (productId > 0)
        {
            //Set Pricelist
            Pricelist pricelist = ol.setPricelist(websiteId, id, eventId);
            if (pricelist.PricelistId != 0)
            {
                //get the pricelistproduct from the pricelist
                PricelistProduct pp = await (from ppx in db.PricelistProducts
                                             where ppx.ProductId == productId
                                             && ppx.PricelistId == pricelist.PricelistId
                                             && ppx.isAvailable == true
                                             && ppx.DiscontinuedDate == null
                                             && ppx.Product.isAvailable == true
                                             && ppx.Product.DiscontinuedDate == null
                                             select ppx).SingleOrDefaultAsync();
                if (pp != null)
                {
                    Order order = new Order();
                    //set some default values for the Order entity
                    if (pricelistProductVM.Order.OrderId == 0)
                    {
                        pricelistProductVM.Order.WebsiteId = websiteId;
                        pricelistProductVM.Order.UserId = userId;
                        pricelistProductVM.Order.EventId = eventId;
                        pricelistProductVM.Order.StartedDate = DateTime.UtcNow;
                        order = pricelistProductVM.Order;
                    }
                    else
                    {
                        order = await db.Orders.FindAsync(pricelistProductVM.Order.OrderId);
                    }

                    //set some default values for the OrderDetails entity
                    pricelistProductVM.Order.OrderDetails.First().InjectFrom(pp);
                    pricelistProductVM.Order.OrderDetails.First().IsPackage = false;

                    //determine if this product should be automatically added to any packages in the order
                    OrderDetail autoFillOd = ol.packageCheck(ref pp, ref pricelistProductVM, ref order, websiteId, db);
                    if (autoFillOd != null)
                    {
                        if (autoFillOd.Quantity > 0)
                        {
                            //This is where the OrderDetail that causes a problem is added
                            pricelistProductVM.Order.OrderDetails.Add(autoFillOd);
                        }
                    }
                    if (pricelistProductVM.Order.OrderId == 0)
                    {

                        db.Orders.Add(order);
                    }
                    else
                    {
                        order.OrderDetails.AddRange(pricelistProductVM.Order.OrderDetails);
                        db.Entry(order).State = EntityState.Modified;
                    }
                    db.SaveChanges();

                }
                else
                {
                    //return error
                    err = "The product was not found in the available pricelist. Please reload your browser and make sure you are signed-in.";
                }
            }
        }
        else
        {
            //return error
            err = "A productId was not passed so no product could not be found. Please reload your browser and make sure you are signed-in.";
        }

        if (err == "")
        {
            ViewBag.data = JsonConvert.SerializeObject(new { Success = 1, Msg = "The product was successfully added to your cart." });
        }
        else
        {
            ViewBag.data = JsonConvert.SerializeObject(new { Success = 0, Msg = err });
        }
        return View();
    }

我感谢您的帮助！