升级到 EF 4.1 后的 DbEntityValidationException

Question

今天我决定升级到 EF 4.1（从 CTP5）。我正在使用代码优先。不幸的是，每当我尝试运行该项目时，都会出现此异常：

System.Data.Entity.Validation.DbEntityValidationException： 一项或多项验证失败 实体。请参阅“实体验证错误” 属性以获取更多详细信息。

EntityValidationErrors 属性并没有真正说明导致异常的实体。 Nether 实际上是 Stack Trace。但是，异常是在 Seed() 覆盖（在初始化程序类中）中显示 context.SaveChanges() 的行上引发的。

经过一些调试和注释掉一些代码后，我认为这与 User、Item 和 Rating 类有关。下面是这些类的代码：

public class User 
{
 public int Id { get; set; }
 public string Nickname { get; set; }
 public string FirstName { get; set; }
 public string LastName { get; set; }
 public string Email { get; set; }
 public string Password { get; set; }
 public float Credits { get; set; }
 public float PromotionalCredits { get; set; }
 public string Telephone { get; set; }
 public string Mobile { get; set; }
 public double RatingAverage { get; set; }
 public string ProfileImage { get; set; }
 public int? DefaultAddressId { get; set; }
 [ForeignKey("DefaultAddressId")]
 public virtual Address DefaultAddress { get; set; }
 public virtual ICollection<Address> Addresses { get; set; }
 public virtual ICollection<Role> Roles { get; set; }
 public virtual ICollection<Comment> Comments { get; set; }
 public virtual ICollection<Item> Items { get; set; }
 public virtual ICollection<Bid> Bids { get; set; }
 public virtual ICollection<CreditCard> CreditCard { get; set; }
 public virtual ICollection<Message> ReceivedMessages { get; set; }
 public virtual ICollection<Message> SentMessages { get; set; }
 public virtual ICollection<Item> WatchList { get; set; }
 public virtual ICollection<Item> ViewList { get; set; }
 public virtual ICollection<Rating> OwnRatings { get; set; }
 public virtual ICollection<Rating> RatingsForOthers { get; set; }
}

public class Item
{
 public int Id { get; set; }
 public string Title { get; set; }
 public string Description { get; set; }
 public float StartingPrice { get; set; }
 public float? BidIncrement { get; set; }
 public DateTime StartDate { get; set; }
 public DateTime EndDate { get; set; }
 public int Status { get; set; }
 [ForeignKey("Status")]
 public virtual ItemStatus ItemStatus { get; set; }
 public virtual Address PickupAddress { get; set; }
 public virtual User User { get; set; }
 public virtual ChildCategory Category { get; set; }
 public virtual ICollection<Comment> Comments { get; set; }
 public virtual ICollection<Image> Images { get; set; }
 public virtual ICollection<Bid> Bids { get; set; }
 public virtual ICollection<User> WatchingUsers { get; set; }
 public virtual ICollection<User> ViewingUsers { get; set; }
 public virtual ICollection<Tag> Tags { get; set; }
}

这是我使用 Seed() 覆盖将一些测试数据添加到数据库的代码：

    var user1 = new User
    {
    FirstName = "John",
    LastName = "Smith",
    Nickname = "J.Smith",
    Email = "john.smith@live.com",
    Password = "myPassword",
    Mobile = "01542367",
    Telephone = "824225523",
    ViewList = new List<Item>(),
    WatchList = new List<Item>(),
    ReceivedMessages = new List<Message>(),
    SentMessages = new List<Message>(),
    Roles = new List<Role>(),
    RatingsForOthers = new List<Rating>(),
    OwnRatings = new List<Rating>(),
    Bids = new List<Bid>(),
    Credits = 600,
    PromotionalCredits = 20,
    ProfileImage = "http://localhost/Content/images/temp/default_profile.jpg",
    Comments = new List<Comment>(),
    Addresses = new List<Address>
                                            {
                                                new Address
                                                    {
                                                        Area = (from c in districts.ElementAt(2).Cities.ElementAt(0).Areas
                                                                    where c.GoogleName.Equals("Sirhmoul")
                                                                    select c).First(),
                                                        Details = "my address in the street",
                                                        Name = "Home Address"
                                                    }
                                            }
};


      var add1 = (from c in user1.Addresses
       where c.Name.Equals("Home Address")
       select c).First();


      var item1 = new Item
      {
      Title = "HTC Desire",
      Description = "Lorem Ipsum is simply dummy text",
      StartingPrice = 400f,
      User = user1,
      EndDate = DateTime.Now.AddDays(10),
      StartDate = DateTime.Now,
      BidIncrement = 3f,
      Status = 1,
      Bids = new List<Bid>(),
      Comments = new List<Comment>(),
      PickupAddress = add1,
      Images = new List<Image>
         {
         new Image
          {
          Description = "some image description",
          Path = "http://localhost:2732/images/temp/dummyItem.png",
          Rank = 1
          },
          new Image
          {
          Description = "some image2 description",
          Path = "http://localhost:2732/Content/images/temp/dummyItem.png",
          Rank = 2
          },
          new Image
          {
          Description = "some image3 description",
          Path = "http://localhost:2732/Content/images/temp/dummyItem.png",
          Rank = 3
          }
         },
      ViewingUsers = new List<User>(),
      WatchingUsers = new List<User>(),
      Tags = new List<Tag>()

      };


      var electronics = (from c in categories
        where c.Name.Equals("Electronics")
        select c).First();

      var cellPhones = (from c in electronics.Children
        where c.Name.Equals("Cell Phones & PDA's")
        select c).First();
      cellPhones.Items.Add(item1);

更新：（清理代码并替换为更新版本）

现在我确定实际上是添加引发异常的项目的代码。我注释掉了创建项目的代码并将 User 实例自己添加到上下文中，然后我运行了该项目，它工作得很好。那么，我在其中创建项目的代码是怎么回事？

注意：在升级到 EF 4.1 之前我没有遇到此问题

有什么建议吗？

谢谢。

Answer 1

最后，这是解决此问题的方法：EF 4.1 RTW Change to Default MaxLength in Code First

Answer 2

我注意到您的标量属性未标记为virtual，但您的导航属性已标记。现在还为时过早弄清楚为什么会产生您所描述的错误，但可能值得更改它以查看它是否有帮助。