EF Core - many to many in class

Question

Friend-Friend Relationship

I find the answer

Entity Framework Core: many-to-many relationships with the same object and try this.

Entitys:

public class User
{
    public int UserId { get; set; }

    public virtual ICollection<Friend> Friends { get; set; }
}

public class Friend
{
    public int MainUserId { get; set; }

    public User ManUser { get; set; }

    public int FriendUserId { get; set; }

    public User FriendUser { get; set; }
}

Free API:

modelBuilder.Entity<Friend>()
    .HasKey(f => new { f.MainUserId, f.FriendUserId });

modelBuilder.Entity<Friend>()
    .HasOne(f => f.ManUser)
    .WithMany(mu => mu.Friends)
    .HasForeignKey(f => f.MainUserId);

modelBuilder.Entity<Friend>()
    .HasOne(f => f.FriendUser)
    .WithMany(mu => mu.Friends)
    .HasForeignKey(f => f.FriendUserId);

When I add-migrate an error message

It is not possible to create a relationship between "User.Friends" and "Friend.FriendUser" because there is already a relationship between "User.Friends" and "Friend.ManUser". Navigation properties can participate in only one relationship.

What should I do? Or should I create Entity FriendEntity: User?

Answer 1

, , " ". Friend , , . MainUser:

public class User
{
    public int UserId { get; set; }
    public virtual ICollection<Friend> MainUserFriends { get; set; }
    public virtual ICollection<Friend> Friends { get; set; }
}

:

modelBuilder.Entity<Friend>()
    .HasKey(f => new { f.MainUserId, f.FriendUserId });

modelBuilder.Entity<Friend>()
    .HasOne(f => f.MainUser)
    .WithMany(mu => mu.MainUserFriends)
    .HasForeignKey(f => f.MainUserId).OnDelete(DeleteBehavior.Restrict);

modelBuilder.Entity<Friend>()
    .HasOne(f => f.FriendUser)
    .WithMany(mu => mu.Friends)
    .HasForeignKey(f => f.FriendUserId);

( ) , .

Answer 2

. de.WithMany() , :

modelBuilder.Entity<Friend>()
    .HasOne(f => f.MainUser)
    .WithMany()
    .HasForeignKey(f => f.MainUserId);

modelBuilder.Entity<Friend>()
    .HasOne(f => f.FriendUser)
    .WithMany()
    .HasForeignKey(f => f.FriendUserId);

: https://github.com/aspnet/EntityFramework/issues/6052