Entity Framework : get related entities - frameworks

Question

I created a WCF service with Entity Framework.
I have 2 tables : Theaters and Locality. Locality as a foreign key in Theaters.
My method :
public theater[] GetTheaters()
{
using (Entities context = new Entities())
{
return context.theater.ToArray();
}
}
I have to remove the "virtual" keyword from "public virtual locality locality { get; set; }" in my theater class. Otherwise, I get a CommunicationException.
But when I do that, I get my list of theaters but the locality is null...
How can I get the locality ?
Thanks
My model class ( I also have other entities) :
public partial class locality
{
public locality()
{
this.theater = new HashSet<theater>();
}
public int idLocality { get; set; }
public int npa { get; set; }
public string locality1 { get; set; }
public ICollection<theater> theater { get; set; }
}
public partial class theater
{
public theater()
{
this.session = new HashSet<session>();
}
public int idTheater { get; set; }
public string name { get; set; }
public string address { get; set; }
public int idLocality { get; set; }
public double latitude { get; set; }
public double longitude { get; set; }
public int seats { get; set; }
public string phone { get; set; }
public string email { get; set; }
public bool threeD { get; set; }
public locality locality { get; set; }
public ICollection<session> session { get; set; }
}
Here is the error that I get :
"Object graph for type 'locality' contains cycles and cannot be serialized if reference tracking is disabled.
EDIT :
The solution that I found :
In my locality class, I had a Collection of theaters.
I had to add "private to the setter like this :
" public ICollection theater { get; private set; }"
So it works, but I still have a problem, I can't access to the theaters from the locality entity anymore. (no more bi-directional)

Answer 1

If you want to force related entities to load, you can use the Include method to do so. By default, related entities are loaded Lazily.
Your example would be:
public theater[] GetTheaters()
{
using (Entities context = new Entities())
{
return context.theater.Include(t=>t.Locality).ToArray();
}
}

Answer 2

You can use eager loading or explicit loading. With eager loading you use the Include extension method:
return context.Theater.Include(t => t.Locality).ToArray();

Answer 3

You're missing the correct annotations to create the relationships. See the code below. (or create the relationships yourself if using the FluentAPI)
Look for the [Key] and [ForeignKey] annotations, as well as the virtual keyword.
public partial class locality
{
public locality()
{
//this.theater = new HashSet<theater>();
}
[Key]
public int idLocality { get; set; }
public int npa { get; set; }
public string locality1 { get; set; }
public virtual ICollection<theater> theaters { get; set; }
}
public partial class theater
{
public theater()
{
//this.session = new HashSet<session>();
}
[Key]
public int idTheater { get; set; }
public string name { get; set; }
public string address { get; set; }
public int idLocality { get; set; }
public double latitude { get; set; }
public double longitude { get; set; }
public int seats { get; set; }
public string phone { get; set; }
public string email { get; set; }
public bool threeD { get; set; }
[ForeignKey("idLocality")]
public virtual locality locality { get; set; }
//public ICollection<session> session { get; set; }
}