title: Optional model property with nested required properties
body: <p>With code like the following:</p>
  
  <pre><code>public class FooModel {
  
      public BarModel Bar { get; set; }
  
  }
  
  public class BarModel {
  
      [Required]
      public string Baz { get; set; }
  
  }
  </code></pre>
  
  <p>I want to render <code>FooModel.Bar</code> in a form, but have it be optional.  However, the form won't submit without any input in the text box for <code>BarModel.Baz</code>.  Is there a way to go about making the nested model in <code>FooModel</code> optional without having to remove the <code>RequiredAttribute</code>?</p>