Question

I have a User class that has many posts and the post class has a user property. My problem is that in the repository to get User, I make a call to the Post repository to get all the user posts. In the repository to get Post, I also make a call to the User repository to get the poster. How do I handle something like this using POCO and repository pattern?

Here is the model.

public class User {
    public IEnumerable<Post> Posts {get; set;}
    /* Other properties here */
}

public class Post {
    public User Poster {get; set;}
    /* Other properties here */
}

repository code:

public IQueryable<User> GetUsers()
{
        return from u in context.Users
               select new User
                          {
                              /*Other properties */
                              Posts = postRepo.GetPostsByUserId(u.UserId)
                          };
}

public IQueryable<Post> GetPostsByUserId(int userId)
{
     //Well, I actually call GetPosts().Where(p => p.PosterId == userId);
     return from p in context.Posts
            select new Post
                      {
                          /*Other properties */
                          Poster = userRepo.GetUsers().Where(u => u.UserId == p.PosterId).SingleOrDefault()
                      };
}

If i make a call to either one, I get the error of Object not instantiated

PS. I just deleted a question targeting the wrong problem, so I made a new question defining the problem correctly.

Answer 1

Your doing it wrong 😉 and ignoring Linq to Sqls ability to correctly generate joins for related entities:

http://msdn.microsoft.com/en-us/library/bb399393.aspx

http://msdn.microsoft.com/en-us/library/system.data.linq.dataloadoptions.loadwith.aspx

---

EF Example:

var postsWithUsers = from p in context.Posts.Include("Users")
                     select new Post

Good documentation:
http://msdn.microsoft.com/en-us/library/bb896272.aspx