How to grab a property object from DB - database

Question

I'm having some doubts, maybe newbie doubts but I just got into ASP.NET MVC 4
Basically I would like to know the correct way of grabbing details of an Object inside a model.
In this case Image inside Contractor.
Model:
public class Contractor {
[Key]
public int ContractorID { get; set; }
[Required]
public string Name { get; set; }
[Required]
public string Address { get; set; }
public Image Avatar { get; set; }
}
public class Image {
[Key]
public int ImageID { get; set; }
[Required]
public string File_name { get; set; }
[Required]
public byte[] File_data { get; set; }
}
public class DATACRUD : DbContext {
public DbSet<Contractor> Companies { get; set; }
public DbSet<Image> Images { get; set; }
}
Controller:
private DATACRUD db = new DATACRUD();
public ActionResult GetContractorAvatar(int id)
{
Contractor contractor = db.Contractors.Find(id);
if (contractor == null)
{
return HttpNotFound();
}
Image avatar = contractor.Avatar;
Problem 1)
avatar == null, but is not suppose to be because when I created the object Contractor, I added the image sucessfully (I checked in the DB and it is there)
The solution I'm seeing is instead of having Image property in Contractor.cs model, I would just put a string property with the image key.
Problem 2)
Even If could grab the image key like I said in the previous problem, when I pass my mouse in Debug mode over
private DATACRUD db = new DATACRUD ();
db.Images is also empty...
return File(avatar.File_data, "image");
}

Answer 1

Because you haven't defined your Image navigation property as virtual, you will have to eager load the Image when loading a Contractor:
db.Contractors.Include("Avatar").SingleOrDefault(c => c.ContractorID == id);
OR
// using System.Data.Entity;
db.Contractors.Include(c => c.Avatar).SingleOrDefault(c => c.ContractorID == id);