How to include sub-entity at ASP.Net MVC3 with Entity Framework

Goog Day!

Can anybody tell how to include sub-entity? I have the Forum project. The page, when I need to display all posts of topic, every post have Post informatin, User information, but, at that time, I need have information of User's group and User's role. (I can't attach image (low reputation), so I try to describe tables by words)

Post: id, Title, Text, UserId // Post.UserId = User.Id

User: id, Name, RoleId, GroupId // User.RoleId = RefRole.Id and User.GroupId = RefGroup.id

RefGroup: id, Name

RefRole: id, Name

If I include just User entity I do it like this:

    public ActionResult ViewTopic (int id)
    {
        ForumDBE forumDB = new ForumDBE();
        var posts = forumDB.Post.Include("User").ToList();
        return View(posts);
    }

But what need I to do, when at var post I need to have RoleName (for exapmple Administrator, Moderator, User) and Group Name (for example Good User, Best User, Advicer...) at View like 开发者_Python百科this?

@model IEnumerable<MvcForum.Models.Post>

@foreach (var post in Model)
{
    User Name:  @post.User.Name
    User Group: @post.User.RefGroup.Name
    Uset Role:  @post.User.RefRole.Name
}

In Entity Framework 4 default configuration you don't have to use Include

public ActionResult ViewTopic (int id)
    {
        ForumDBE forumDB = new ForumDBE();
        var posts = forumDB.Post; // or you can use .ToList() but I prefer to use IQueryable
        return View(posts);
    }

then

@model IQueryable<MvcForum.Models.Post>

@foreach (var post in Model)
{
    User Name:  @post.User.Name
    User Group: @post.User.RefGroup.Name
    Uset Role:  @post.User.RefRole.Name
}

It will use lazy loading since you are using IQueryable and not IEnumerable