EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType

Question

I am working with Entity Framework Code First and MVC 5. When I created my application with Individual User Accounts Authentication I was given an Account controller and along with it all the required classes and code that is needed to get the Indiv User Accounts authentication to work.

Among the code already in place was this:

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext() : base("DXContext", throwIfV1Schema: false)
    {

    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }
}

But then I went ahead and created my own context using code first, so I now have the following too:

public class DXContext : DbContext
{
    public DXContext() : base("DXContext")
    {
        
    }

    public DbSet<ApplicationUser> Users { get; set; }
    public DbSet<IdentityRole> Roles { get; set; }
    public DbSet<Artist> Artists { get; set; }
    public DbSet<Paintings> Paintings { get; set; }        
}

Finally I have the following seed method to add some data for me to work with whilst developing:

protected override void Seed(DXContext context)
{
    try
    {

        if (!context.Roles.Any(r => r.Name == "Admin"))
        {
            var store = new RoleStore<IdentityRole>(context);
            var manager = new RoleManager<IdentityRole>(store);
            var role = new IdentityRole { Name = "Admin" };

            manager.Create(role);
        }

        context.SaveChanges();

        if (!context.Users.Any(u => u.UserName == "James"))
        {
            var store = new UserStore<ApplicationUser>(context);
            var manager = new UserManager<ApplicationUser>(store);
            var user = new ApplicationUser { UserName = "James" };

            manager.Create(user, "ChangeAsap1@");
            manager.AddToRole(user.Id, "Admin");
        }

        context.SaveChanges();

        string userId = "";

        userId = context.Users.FirstOrDefault().Id;

        var artists = new List<Artist>
        {
            new Artist { FName = "Salvador", LName = "Dali", ImgURL = "http://i62.tinypic.com/ss8txxn.jpg", UrlFriendly = "salvador-dali", Verified = true, ApplicationUserId = userId },
        };

        artists.ForEach(a => context.Artists.Add(a));
        context.SaveChanges();

        var paintings = new List<Painting>
        {
            new Painting { Title = "The Persistence of Memory", ImgUrl = "http://i62.tinypic.com/xx8tssn.jpg", ArtistId = 1, Verified = true, ApplicationUserId = userId }
        };

        paintings.ForEach(p => context.Paintings.Add(p));
        context.SaveChanges();
    }
    catch (DbEntityValidationException ex)
    {
        foreach (var validationErrors in ex.EntityValidationErrors)
        {
            foreach (var validationError in validationErrors.ValidationErrors)
            {
                Trace.TraceInformation("Property: {0} Error: {1}", validationError.PropertyName, validationError.ErrorMessage);
            }
        }
    }
    
}

My solution builds fine, but when I try and access a controller that requires access to the database I get the following error:

DX.DOMAIN.Context.IdentityUserLogin: : EntityType 'IdentityUserLogin' has no key defined. Define the key for this EntityType.

DX.DOMAIN.Context.IdentityUserRole: : EntityType 'IdentityUserRole' has no key defined. Define the key for this EntityType.

What am I doing wrong? Is it because I have two contexts?

UPDATE

After reading Augusto's reply, I went with Option 3. Here is what my DXContext class looks like now:

public class DXContext : DbContext
{
    public DXContext() : base("DXContext")
    {
        // remove default initializer
        Database.SetInitializer<DXContext>(null);
        Configuration.LazyLoadingEnabled = false;
        Configuration.ProxyCreationEnabled = false;

    }

    public DbSet<User> Users { get; set; }
    public DbSet<Role> Roles { get; set; }
    public DbSet<Artist> Artists { get; set; }
    public DbSet<Painting> Paintings { get; set; }

    public static DXContext Create()
    {
        return new DXContext();
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<User>().ToTable("Users");
        modelBuilder.Entity<Role>().ToTable("Roles");
    }

    public DbQuery<T> Query<T>() where T : class
    {
        return Set<T>().AsNoTracking();
    }
}

I also added a User.cs and a Role.cs class, they look like this:

public class User
{
    public int Id { get; set; }
    public string FName { get; set; }
    public string LName { get; set; }
}

public class Role
{
    public int Id { set; get; }
    public string Name { set; get; }
}

I wasn't sure if I would need a password property on the user, since the default ApplicationUser has that and a bunch of other fields!

Anyways, the above change builds fine, but again I get this error when the application is ran:

Invalid Column name UserId

UserId is an integer property on my Artist.cs

Answer 1

In my case I had inherited from the IdentityDbContext correctly (with my own custom types and key defined) but had inadvertantly removed the call to the base class's OnModelCreating:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder); // I had removed this
    /// Rest of on model creating here.
}

Which then fixed up my missing indexes from the identity classes and I could then generate migrations and enable migrations appropriately.