Entity Framework always includes data that is in context even if I don't ask for it

Question

I am using MVC.NET web api, EF with DB first, and I have lazy loading turned off on my context. EF is returning way too much data, even with LazyLoading turned off.

For example, I have Users with one Role. When I query for Users and Include Role, the Role.Users property is automatically filled with data since Users have been loaded into the context.

Why can't I get EF to give me JUST what I request? Or am I missing something big here?

public partial class User
{
    public int UserID { get; set; }
    public string Title { get; set; }
    public string Email { get; set; }
    public int RoleID { get; set; }

    ....

    public virtual Role Role { get; set; }
} 

public partial class Role
{
    public int RoleID { get; set; }
    public string RoleName { get; set; }

    ....

    public virtual ICollection<User> Users { get; set; }
} 




return db.Users.Include(u => u.Role);
// ^^ user.Role.Users is filled with 1000s of users

TL;DR - I want EF to never load data into navigation properties/collections unless I .Include() it directly. When serializing to JSON I want just what I ask for explicitly. It seems that even with lazy loading off, navigation properties that are already in the context (ie usually "circular references") will be loaded and returned.

Answer 1

The behaviour your are seeing is called Relationship Fixup and you cannot disable it.

If you are loading users with roles to serialize them and sent them to somewhere I guess that you don't want to track changes of entities in the context they have been loaded in. So, there is no need to attach them to the context and you can use:

return db.Users.Include(u => u.Role).AsNoTracking();

Or use a projection into an object specialized for serialization, as suggested by @STLRick.

Answer 2

You can select only what you need by using Select().

var users = _db.Users.Select(x => new
{
    UserID = x.UserID,
    Title = x.Title,
    Email = x.Email,
    RoleID = x.RoleID
}).AsEnumerable();