EF Code First - Include(x => x.Properties.Entity) a 1 : Many association - c#-4.0

Question

Given a EF-Code First CTP5 entity layout like:
public class Person { ... }
which has a collection of:
public class Address { ... }
which has a single association of:
public class Mailbox { ... }
I want to do:
PersonQuery.Include(x => x.Addresses).Include("Addresses.Mailbox")
WITHOUT using a magic string. I want to do it using a lambda expression.
I am aware what I typed above will compile and will bring back all Persons matching the search criteria with their addresses and each addresses' mailbox eager loaded, but it's in a string which irritates me.
How do I do it without a string?
Thanks Stack!

Answer 1

For that you can use the Select method:
PersonQuery.Include(x => x.Addresses.Select(a => a.Mailbox));
You can find other examples in here and here.

Answer 2

For any one thats still looking for a solution to this, the Lambda includes is part of EF 4+ and it is in the System.Data.Entity namespace; examples here
http://romiller.com/2010/07/14/ef-ctp4-tips-tricks-include-with-lambda/

Answer 3

It is described in this post: http://www.thomaslevesque.com/2010/10/03/entity-framework-using-include-with-lambda-expressions/
Edit (By Asker for readability):
The part you are looking for is below:
public static class ObjectQueryExtensions
{
public static ObjectQuery<T> Include<T>(this ObjectQuery<T> query, Expression<Func<T, object>> selector)
{
string path = new PropertyPathVisitor().GetPropertyPath(selector);
return query.Include(path);
}
class PropertyPathVisitor : ExpressionVisitor
{
private Stack<string> _stack;
public string GetPropertyPath(Expression expression)
{
_stack = new Stack<string>();
Visit(expression);
return _stack
.Aggregate(
new StringBuilder(),
(sb, name) =>
(sb.Length > 0 ? sb.Append(".") : sb).Append(name))
.ToString();
}
protected override Expression VisitMember(MemberExpression expression)
{
if (_stack != null)
_stack.Push(expression.Member.Name);
return base.VisitMember(expression);
}
protected override Expression VisitMethodCall(MethodCallExpression expression)
{
if (IsLinqOperator(expression.Method))
{
for (int i = 1; i < expression.Arguments.Count; i++)
{
Visit(expression.Arguments[i]);
}
Visit(expression.Arguments[0]);
return expression;
}
return base.VisitMethodCall(expression);
}
private static bool IsLinqOperator(MethodInfo method)
{
if (method.DeclaringType != typeof(Queryable) && method.DeclaringType != typeof(Enumerable))
return false;
return Attribute.GetCustomAttribute(method, typeof(ExtensionAttribute)) != null;
}
}
}