Self-referencing many-to-many recursive relationship code first Entity Framework

c# entity-framework many-to-many code-first
Korayem picture Korayem · Feb 26, 2011 · Viewed 18.2k times · Source

I can't seem to make this work at all

class Member
{
    public virtual IList<Member> Friends { get; set; }
    [Key]
    public int MemberId { get; set; }
    public string Name{ get; set; }
}

I tried adding Mappings but in vain. Is there a way to do so with CTP5?

Answer

Morteza Manavi picture Morteza Manavi · Feb 26, 2011

By convention, Code First will take uni-directional associations as one to many. Therefore you need to use fluent API to let Code First know that you want to have a many to many self referencing association:

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Member>().HasMany(m => m.Friends).WithMany().Map(m =>
        {
            m.MapLeftKey("MemberId");
            m.MapRightKey("FriendId");
            m.ToTable("MembersFriends");
        }
    );
}

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