title: Mvc retain values after postback
body: <p>I have a simple TestController class and User model:</p>
  
  <pre><code>public class TestController : Controller
  {
      public ActionResult TestAction()
      {
          return View();
      }
  
      [HttpPost]
      public ActionResult TestAction(User user)
      {
          return View();
      }
  }
  
  public class User
  {
      public int Id { get; set; }
  
      public string Name { get; set; }
  
      public int Age { get; set; }
  }
  </code></pre>
  
  <p>This is my form:</p>
  
  <p><a href="https://i.stack.imgur.com/TiFUv.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TiFUv.png" alt="enter image description here"></a></p>
  
  <p>As far as I know MVC is stateless and it does not have a viewstate concept. But after posting the data to my controller and when I return the view, all my data is there. I expect empty fields but they are all filled with the posted data. I could not understand how MVC knows the values after postback?</p>