Object property is null after taking data from DB. Entity Framework - database

Question

I have a DBContext that is initializing through DropCreateDatabaseAlways class.
In the Seed method I have this code:
base.Seed(context);
var c1 = new Company { Name = "Samsung"};
var c2 = new Company { Name = "Microsoft"};
context.Companies.AddRange(new List<Company>{c1,c2 });
var phones = new List<Phone>
{
new Phone("Samsung Galaxy S5", 20000, c1),
new Phone("Nokia S1243", 200000, c1),
new Phone("Nokia 930", 10000, c2),
new Phone("Nokia 890", 8900, c2)
};
context.Phones.AddRange(phones);
context.SaveChanges();
And if iterate through phones now, I see that phone.Company is not null.
But when I do this in any other piece of code, phone.Company IS null.
What do I do wrong?
A simple piece of code with null phone.Company:
using (var db = new MyDataModel())
{
var phonesList = db.Phones.ToList();
foreach (var p in phones)
{
System.Console.WriteLine($"Name: {p.Name}
Company: {p.Company}"); // Company is null.
}
}
I can access Company using Join with Companies on phone.companyId, so Companies table exists in DB.
My DataModel class:
public class MyDataModel : DbContext
{
public MyDataModel()
: base("name=MyDataModel")
{
}
static MyDataModel()
{
Database.SetInitializer(new MyContextInializer());
}
public DbSet<Company> Companies { get; set; }
public DbSet<Phone> Phones { get; set; }
}
My Phone class:
namespace DataContext
{
public class Phone
{
public Phone()
{
}
public Phone(string name, int price, Company company)
{
Name = name;
Price = price;
Company = company;
}
public int Id { get; set; }
public string Name { get; set; }
public int Price { get; set; }
public int CompanyId { get; set; }
public Company Company { get; set; }
}
}

Answer 1

If you want to automagically load the companies when you load a phone, you need to add the virtual keyword before the Company property.
public class Phone {
public Phone() {
}
public Phone(string name, int price, Company company)
{
Name = name;
Price = price;
Company = company;
}
public int Id { get; set; }
public string Name { get; set; }
public int Price { get; set; }
public int CompanyId { get; set; }
public virtual Company Company { get; set; }
}
This tells entity framework to automatically load the linked company whenever you retrieve a phone from the database.
Alternatively you can use eager loading when performing a query on phones.
var phones = MyDataModel.Phones.Include(x => x.Company).ToList();

Answer 2

In addition to the cool answer from Immorality, I'll place here these links:
Virtual properties
MSDN - Loading related data strategies