EF Code首先,如何从一个表到另一个表实现两个外键？

Question

我最近下载了Entity Framework Code First CTP5,并且遇到了这种情况的麻烦.我有两张表如下:

Members table :
  ID  
  Name

Comments table :  
  ID  
  Comment  
  CommentedMemberID  
  CommentMemberID  

而且,数据应如下所示:

Members  
ID Name   
1  Mike  
2  John  
3  Tom  

Comments  
ID Comment CommentedMemberID CommentMemberID  
1  Good 1 2       
2  Good 1 3  
3  Bad  2 1  

然后,我编码如下:

public class Member
{
    public int ID {get; set; }
    public string Name { get; set;}
    public virtual ICollection<Comment> Comments { get; set;}
}

public class Comment
{
    public int ID { get; set; }
    public string Comment { get; set; }
    public int CommentedMemberID { get; set; }
    public int CommentMemberID{ get; set; }

    public virtual Member CommentedMember { get; set; }
    public virtual Member CommentMember { get; set; }
}

public class TestContext : DbContext
{
    public DbSet<Member> Members { get; set; }
    public DbSet<Comment> Comments { get; set; }
}

但是当我在我的上运行这些模型时cshtml,它会给我错误说"无法创建CommentMember实例"或类似的东西(抱歉,我已经更改了我的模型以进行EF Code First评估,因此无法重现相同的错误).

我也试着使用OnModelCreating上TestContext,却找不到任何好的说明,不知道该怎么办.我看到了EF Code First CTP3的博客文章,似乎该版本中有一个RelatedTo属性,但现在它已经消失了.

谁能知道如何让它正常工作？或者这是完全错误的方式吗？

谢谢,
Yoo

Answer 1

这是一种特殊情况,您需要使用流畅的API来配置您的关联.这样就可以了:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Comment>().HasRequired(c => c.CommentedMember)
                                  .WithMany(m => m.Comments)
                                  .HasForeignKey(c => c.CommentedMemberID)
                                  .WillCascadeOnDelete();

    modelBuilder.Entity<Comment>().HasRequired(c => c.CommentMember)
                                  .WithMany()
                                  .HasForeignKey(c => c.CommentMemberID)
                                  .WillCascadeOnDelete(false);
}