entity-framework - EF4.1 代码第一对多自引用

Question

我试图首先使用 EF4.1 代码进行一对多的自我引用。我的实体看起来像这样

public class Site
{
    public int Id { get; set; }
    public int? ParentId { get; set; }
    public string Sitename { get; set; }

    public virtual Site ChildSite { get; set; }
    public virtual ICollection<Site> ChildSites { get; set; }
}

在我的上下文类中，我这样做是为了进行自我引用

modelBuilder.Entity<Site>()
    .HasOptional(s => s.ChildSite)
    .WithMany(s => s.ChildSites)
    .HasForeignKey(s => s.ParentId);

但是当我尝试使用此代码将一些虚拟数据添加到我的数据库时

var sites = new List<Site>
{
    new Site { ParentId = 0, Sitename = "Top 1" },
    new Site { ParentId = 0, Sitename = "Top 2" },
    new Site { ParentId = 0, Sitename = "Top 3" },
    new Site { ParentId = 0, Sitename = "Top 4" },
    new Site { ParentId = 1, Sitename = "Sub 1_5" },
    new Site { ParentId = 1, Sitename = "Sub 1_6" },
    new Site { ParentId = 1, Sitename = "Sub 1_7" },
    new Site { ParentId = 1, Sitename = "Sub 1_8" },
    new Site { ParentId = 2, Sitename = "Sub 2_9" },
    new Site { ParentId = 2, Sitename = "Sub 2_10" },
    new Site { ParentId = 2, Sitename = "Sub 2_11" },
    new Site { ParentId = 2, Sitename = "Sub 2_12" },
    new Site { ParentId = 3, Sitename = "Sub 3_13" },
    new Site { ParentId = 3, Sitename = "Sub 3_14" },
    new Site { ParentId = 3, Sitename = "Sub 3_15" },
    new Site { ParentId = 3, Sitename = "Sub 3_16" },
    new Site { ParentId = 4, Sitename = "Sub 4_17" },
    new Site { ParentId = 4, Sitename = "Sub 4_18" },
    new Site { ParentId = 4, Sitename = "Sub 4_19" },
    new Site { ParentId = 4, Sitename = "Sub 4_20" }
};
sites.ForEach(s => context.Sites.Add(s));
context.SaveChanges();

我收到此错误:

Unable to determine the principal end of the 'Cms.Model.Site_ChildSite' relationship. Multiple added entities may have the same primary key.

我在这里错过了什么？

编辑:

这是我的问题的解决方案。我删除了 public virtual Site ChildSite { get; set; }从实体

public class Site
{
    public int Id { get; set; }
    public int? ParentId { get; set; }
    public string Sitename { get; set; }

    public virtual ICollection<Site> ChildSites { get; set; }
}

然后我更改了 modelBuilder对此

modelBuilder.Entity<Site>()
    .HasMany(s => s.ChildSites)
    .WithOptional()
    .HasForeignKey(s => s.ParentId);

由于似乎数据库的自动生成不起作用，我继续像这样自己创建了表

int Id, not null, primary key
int ParentId, null
string Sitename, null

一切都如我所愿。

第二次编辑

以及让虚拟数据自动生成工作的最后一步

var parent1 = new Site
{
    Sitename = "Top 1",
    ChildSites = new List<Site>
        {
            new Site {Sitename = "Sub 1_5"},
            new Site {Sitename = "Sub 1_6"},
            new Site {Sitename = "Sub 1_7"},
            new Site {Sitename = "Sub 1_8"}
        }
};

ect . . . 

context.Sites.Add(parent1);
context.SaveChanges();

请参阅下面的 Slauma 答案

Answer 1

我有一个不同的模型，但我会发布我的案例中必要的东西，它在 MVC 3 上与 EF4.1 一起工作得很好:

型号

public class Page
{
    public int Id { get; set; }
    public virtual string Title { get; set; }

    public int? ParentId { get; set; }
    public virtual Page Parent { get; set; }
    public virtual ICollection<Page> Children { get; set; }
}

数据库 (使用流畅的API)

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
     modelBuilder.Entity<Page>()
                 .HasOptional(s => s.Parent)
                 .WithMany(s => s.Children)
                 .HasForeignKey(s => s.ParentId);
}

初始化程序

var page1 = new Page()
{
     Title = "title"
};

context.Pages.Add(page1);

var page2 = new Page()
{
      Parent = page1,
      Title = "title2",
};

context.Pages.Add(page2);