Entity Framework 4.1 eager loading - on abstract classes

I'm using EF 4.1 at Code First approach. I have an abstract class:

public abstract class Base
{
}

And two dereived classes:

public Class Derived1 : Base
{
     public Division division{ get; set; }
}

public Class Derived2 : Base
{
     public Brand brand{ get; set; }
}

At last, I have a query that selects a list of the Base class, and i want to perform eager loading, but i don't know who my derived classes are:

using (var db = new MyContext())
{
     var lst = db.Base.Include(WHAT SHOULD I WRITE HERE).ToList();
}开发者_开发百科

Any Ideas?

You must do this:

var lst = db.Base.OfType<Derived1>().Include(d => division)
            .Union(
               db.Base.OfType<Derived2>().Include(d => d.brand))
            .ToList();