title: Model's property is null when viewing detail
body: <p>I have defined a model, Item, which has the following properties:</p>
  
  <pre><code>public class Item
  {
      public bool Active { get; set; }
      public string ItemCode { get; set; }
  
      public int ItemId { get; set; }
      public string Name { get; set; }
  
      public Category Category { get; set; }
      public int CategoryId { get; set; }
  
  }
  </code></pre>
  
  <p>I am trying to reference the Category from within the detail view on the Item controller. My code in the controller is:</p>
  
  <pre><code>public ActionResult Details(int id = 0)
  {
      Item item = db.Items.Find(id);
      if (item == null)
      {
          return HttpNotFound();
      }
      return View(item);
  }
  </code></pre>
  
  <p>However, when I explore the item object here I can see the CategoryId is correctly set, the Category property is set to null. Therefore when I reference Item.Category.Name I am getting a blank result. I have tried making my properties virtual (following a tutorial on-line) but this didn't seem to fix the issue. What am I doing wrong?</p>