title: How do I show a different Required message to instances of the same object in MVC3?
body: <p>I have a Razor MVC3 project which has two user records in a form, one for the key contact and one for a backup contact. For example;</p>
  
  <pre><code>public class User
  {
      [Required(ErrorMessage = "First name is required")]
      public string FirstName { get; set; }
  }
  </code></pre>
  
  <p>Validation all works well except for the small issue where the user fails to fill out a field, it says 'First name is required' but I'd like to point the user to which one of the first name fields is missing. Such as 'Backup contact first name is required' or 'Key contact first name is required'.</p>
  
  <p>Ideally I'd like to leave the [Required] annotation on the class as it is used elsewhere.</p>
  
  <p>This seems like one of those small cases that might have been missed and is not easily achieved, but please prove me wrong.</p>
  
  <p>Ryan</p>