title: Json.Net: Serialize/Deserialize property as a value, not as an object
body: <p>How can I achieve the following JSON representation of Id class when used in another class?</p>
  
  <pre><code>class Car
  {
      public StringId Id { get; set; }
      public string Name { get; set; }
  }
  
  class StringId
  {
      public string Value { get; set; }
  }
  
  // ---------------------------------------------
  
  // Desired representation
  { "Id": "someId", "Name": "Ford" }
  
  // Default (undesired) representation
  { "Id" : { "Value": "someId" }, "Name": "Ford" }
  </code></pre>