Many-To-Many relationship deleting join table on third addition of ICollection

Question

I'm having an issue with my site. I have a UserProfile class with two navigation properties at the bottom of my file as follows;

public virtual ICollection<UserProfile> Followers { get; set; }
public virtual ICollection<UserProfile> Following { get; set; }

This then creates another table (which I believe is called the intersect table?) in which it manages this relationship by itself. This works fine and I can add/remove from this List. The part i'm having trouble with is when I want to add another navigation property called "BlockedUsers", so it's like this;

public virtual ICollection<UserProfile> Followers { get; set; }
public virtual ICollection<UserProfile> Following { get; set; }
public virtual ICollection<UserProfile> BlockedUsers { get; set; }

When I run Add-Migration and Update-Database, it deletes the table it created previously for my Following/Followers List and breaks my sites feature therefore I'm unable to add/remove from the Following/Followers List.

Why is it doing this and how can I resolve it?

Thanks,

Owen

Answer 1

I've managed to work this out using FluentAPI. I've not really looked into it before but I realised it was the only way to achieve what I was trying to do.

If you take the first block of navigation properties (Following/Follower) this will create an intersect table. However, if I add the third navigation property to do the same thing, it'll delete this table.

In order to have both tables for BlockedUsers and Following/Followers, I had to use FluentAPI to create this intersect manually.

Here is what I added to my IdentityModel.cs -

protected override void OnModelCreating( DbModelBuilder modelBuilder)
    {
        // Sets up Many-To-Many relationship for Following/Followers UserProfiles
        modelBuilder.Entity<UserProfile>()
        .HasMany( t => t.Followers )
        .WithMany( t => t.Following );

        // Sets up Many-To-Many relationship for Blocked UserProfiles
        modelBuilder.Entity<UserProfile>()
        .HasMany( t => t.BlockedUsers )
        .WithMany();

        base.OnModelCreating( modelBuilder );
    }

I hope this helps someone with the same issue.

I am however still wondering why it deleted the table in the first place before I added any FluentAPI code.