Question

I have something like this:

public class Category
{
    [Key]
    public int Id { get; set; }

    public string Name { get; set; }
    public List<Thread> Threads { get; set; }
}
public class Thread
{
    [Key]
    public int Id { get; set; }

    public List<Post> Posts { get; set; }
}

public class Post
{
    [Key]
    public int Id { get; set; }
}

And i don’t know how to add a thread item to an existing category. I tried something like this:

var context = new Db();
var thr = new Thread
        {...(adding new Post item here, not important since this works perfectly)...};
context.Categories.Single(c => c.Name == "some_category").Threads.Add(thr);

But this obviously doesn’t want to work.

Answer 1

Are you actually adding new Thread item to your context so that it’s tracked? If you’re context doesn’t know it exists, it won’t add it to the database.

var context = new Db();
var thr = new Thread
        {...(adding new Post item here, not important since this works perfectly)...};

//add thread to context
context.Threads.Add(thr);

context.Categories.Single(c => c.Name == "some_category").Threads.Add(thr);