Entity Framework explicitly included navigation property is null

Question

I've got lazy loading off, and proxy creation doesn't matter (tried both true and false, no difference).

I have this model:

public class Comment{

    [Required]
    public int SenderID { get; set; }

    public User Sender { get; set; }

}

(and of course, I have a user class).

At database level, I confirm that the Sender is a valid User object. I have some IQueryable<Comment> named commentsQuery (that basically takes some comments from a post. Then I include the Sender navigation property and execute the query:

var comments = commentsQuery.Take(50).OrderBy(c => c.ID).Include(c => c.Sender).ToList();

However, some comment objects inside the list have their Sender set to null even though I've explicitly included the navigation property.

If I turn on lazy loading it works correctly, but I don't want to turn on lazy loading.

Why is the explicitly-included required navigation property null? (I'm on Entity Framework 6.1.3)

Can Poyrazoğlu Can Poyrazoğlu · Accepted Answer · 2016-12-01T13:46:56

Okay, just figured out myself. I had to include the sender at the original query when I'm constructing it from the database context.

I was using:

 var post = await Database.Posts.Where(p => p.ID == postId && p.Sender.Username == username).Include(p => p.Sender).Include(p => p.Comments).FirstOrDefaultAsync();
 IQueryable<Comment> commentsQuery = post.Comments.ActiveObjects().OrderByDescending(c => c.ID).AsQueryable();

And then, I assume Entity Framework was just ignoring (I think it's a design issue at Microsoft's side) the later-included navigation property (commentsQuery.[...].Include(c => c.Sender)).

I've modified the original query to include the second-level navigation property:

var post = await Database.Posts.Where(p => p.ID == postId && p.Sender.Username == username).Include(p => p.Sender).Include(p => p.Comments).Include(p => p.Comments.Select(c => c.Sender)).FirstOrDefaultAsync();

(notice the addition of .Include(p => p.Comments.Select(c => c.Sender))

Now, my query works properly. I'm not sure if it's the best way to do it though, anyway, it's not the scope of this question.

Entity Framework explicitly included navigation property is null

1 Answers