Explicit loading of grandchild collections in EF 4.1

Question

Given the following model ...

public class Parent {     public int Id { get; set; }     public ICollection<Child> Children { get; set; } }  public class Child {     public int Id { get; set; }     public ICollection<Grandchild> Grandchildren { get; set; } }  public class Grandchild {     public int Id { get; set; } } 

... we can eager load with Include a Parent with all Children and Grandchildren in one step like so:

context.Parents.Include(p => p.Children.Select(c => c.Grandchildren)) 

Is something similar possible for explicit loading?

The child collection can be explicitely loaded this way:

Parent parent = context.Parents.Find(parentId); context.Entry(parent).Collection(p => p.Children).Load(); 

But trying to load the children in a similar way as with Include ...

context.Entry(parent)     .Collection(p => p.Children.Select(c => c.Grandchildren)).Load(); 

... doesn't compile und the string overload of Collection ...

context.Entry(parent).Collection("Children.Grandchildren").Load(); 

... throws an exception ("...no dotted paths allowed...").

The only thing which I found working is to explicitely load the Grandchildren in a loop:

Parent parent = context.Parents.Find(parentId); context.Entry(parent).Collection(p => p.Children).Load(); foreach (var child in parent.Children)     context.Entry(child).Collection(c => c.GrandChildren).Load(); 

I am wondering if I missed something and if there is some other way to explicitely load the GrandChildren in one roundtrip.

Thanks for feedback in advance!

Answer 1

As I pointed in the comment you can try to get query for relation first, then add includes and execute loading. Something like:

context.Entry(parent)        .Collection(p => p.Children)        .Query()        .Include(c => c.Grandchildren) // I'm not sure if you can include grandchild directly          .Load();