how to use eager loading without string for related entities?

Question

I would like to use eager loading for load related entities and I see this page:

In this example I can see that there are two ways to get the related entities:

var princesses1 = context.Princesses
                          .Include(p => p.Unicorns)
                          .ToList();


var princesses1 = context.Princesses
                          .Include("Unicorns")
                          .ToList();

The first way is to use the lambda expression (I think that correct name is that, if not, correct me), and the second way is to use a string with the name of the related entity.

In my case, I can use the second, because in the firt way, when I can't get the property of the related entity in the lambda expression. I use this code:

IQueryable<Customers> myQuery;
myQuery = myContext.Customers.Include("Orders");

But if I try to use the second way:

IQueryable<Customers> myQuery;
myQuery = myContext.Customers.Include(c=>c.?????);

I can't select the Orders property.

Why?

score 2 · Answer 1 · answered Jul 31 '13 at 15:33

2

You should use System.Data.Entity in order to be able to use lambda expression in Include method:

using System.Data.Entity;

answered Jul 31 '13 at 15:33

cuongle

74,024
28
151
206

1

Yes, thaks, I use to include this, but in this class not. Thanks. – Álvaro García Jul 31 '13 at 15:36

score 1 · Accepted Answer · answered Jul 31 '13 at 15:33

1

Add this to the top of your file:

using System.Data.Entity;

This includes a reference to a DbExtensions class which provides the include extension method.

answered Jul 31 '13 at 15:33

Sethcran

798
5
11

how to use eager loading without string for related entities?

2 Answers2