实体框架6具有多重性1或0..1

Question

在模型绑定器创建模型，子代和孙代，然后使用context.SaveChanges（）;尝试将对象插入子集合中时，出现以下错误。

违反多重性约束。 关系“ PPLib.Models.OrderDetail_OrderDetailPricelistProductOptions”的角色“ OrderDetail_OrderDetailPricelistProductOptions_Source”具有多重性1或0.1.1。

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; }

}

要更清楚：

如果我提交一个完整的新Order，其中包含OrderDetails列表，OrderDetailPricelistProductOptions列表以及OrderDetailPricelistProductOptionsDetails列表，则模型绑定程序将执行其工作，并且在执行此操作时不会收到任何错误：

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

如果提交带有现有订单的编辑和新建的OrderDetails列表，OrderDetailPricelistProductOptions列表及其OrderDetailPricelistProductOptionsDetails列表，则可以从数据库上下文中获取Order，然后使用以下方法从视图模型中合并OrderDetails：

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

而且我没有收到任何错误消息：

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Model Binder组装的现有OrderDetails中注入其值。 我更改其数量值，然后将其添加到ViewModel中的OrderDetails集合中，如下所示：

pricelistProductVM.Order.OrderDetails.Add(autoFillOd);

当我执行db.SaveChanges（）时，收到错误消息。

您会注意到该错误是在OrderDetails的子级上：OrderDetail_OrderDetailPricelistProductOptions_Source

为什么不能将OrderDetail动态添加到OrderDetails的集合中？ 所有OrderDetails是新的（将要插入），因此副本之间的值相同，但“数量”属性除外，这应该不是问题。

控制器动作如下：

[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();
    }

感谢您的帮助！

Answer 1

我认为OrderDetailPricelistProductOption.OrderDetailId不能单一->应该是列表，因为它可以出现在许多OrderDetails中...