title: string.empty converted to null when passing JSON object to MVC Controller
body: <p>I'm passing an object from client to server. Properties of the object which are represented as string.empty are being converted to null during this process. I was wondering how to prevent this when the objects type supports string.empty.</p>
  
  <p><img src="https://i.stack.imgur.com/sXUIT.png" alt="enter image description here"></p>
  
  <pre><code>console.log("DataToPost:", dataToPost);
  
  $.ajax({
      type: "POST",
      contentType: 'application/json'
      url: "../../csweb/Orders/SaveOrderDetails/",
      data: dataToPost,
      success: function (result) {
          console.log(result);
      },
      error: function (e) {
          console.error(e);
      }
  });
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/a9q4a.png" alt="enter image description here"></p>
  
  <p>My model includes nullable DateTime objects. I cannot force all nulls to string.empty on the server.</p>
  
  <p>I am using AutoMapper, so I would prefer not to have to inspect properties individually on the server.</p>