title: Data annotations not working in view model
body: <p>I have a few different models with properties that I've decorated with data annotations for validation.</p>
  
  <pre><code>public class BillingModel
  {
      [Required,
      DisplayName("First Name")]
      public string FirstName { get; set; }
  
      [Required,
      DisplayName("Last Name")]
      public string LastName { get; set; }
  }
  
  public class CustomerModel
  {
      [Required,
      DisplayName("Address")]
      public string Adress { get; set; }
  
      [Required,
      DisplayName("City")]
      public string City { get; set; }
  }
  </code></pre>
  
  <p>When I put them in a view model like this:</p>
  
  <pre><code>public class OrderViewModel
  {
      public BillingModel Billing { get; set; }
      public CustomerModel Customer { get; set; }
  }
  </code></pre>
  
  <p>They render out like this:</p>
  
  <pre><code>&lt;input id="Business_FirstName" name="Business.FirstName" type="text" value="" /&gt;
  
  &lt;input id="Business_LastName" name="Business.LastName" type="text" value="" /&gt;
  </code></pre>
  
  <p>My Razor looks like this:</p>
  
  <pre><code>@Html.TextBoxFor(x =&gt; x.Business.FirstName)
  @Html.TextBoxFor(x =&gt; x.Business.LastName)
  </code></pre>
  
  <p>I have many properties that need to live in their own classes as each class contains specific methods. Even if I put <code>[Required]</code> on each property in the View Model it still doesn't work.</p>