title: PartialViews display not updated model
body: <p>I have problems with PartialViews using ASP.NET MVC3 (Razor) and Ajax.
  This is my case:<br>
  I have simple test viewmodel:   </p>
  
  <pre><code>public class MyModel
  {
      public string MyText { get; set; }
      public int MyNumber { get; set; }
  }
  </code></pre>
  
  <p>My target is to have a form. Depending on posted data I would like to display different partial views. 
  I've created main form (Index view): </p>
  
  <pre><code>@using (Ajax.BeginForm("Index", "Test", new AjaxOptions() { HttpMethod = "POST", UpdateTargetId = "testdiv" }))
  {
      &lt;div id="testdiv"&gt;
  
  
          @Html.Partial("Cat")
  
      &lt;/div&gt;
      &lt;input type="submit" value="Go" /&gt;
  }
  </code></pre>
  
  <p>I've created two different partial views which should be shown when main form posted (depending on posted data):
  Cat View:</p>
  
  <pre><code>&lt;span&gt;cat view&lt;/span&gt;
  @Html.TextBoxFor(m=&gt; m.MyText)
  @Html.TextBoxFor(m=&gt; m.MyNumber)
  &lt;span&gt;@DateTime.Now.Second&lt;/span&gt;
  </code></pre>
  
  <p>Dog View:</p>
  
  <pre><code>&lt;span&gt;dog view&lt;/span&gt;
  @Html.TextBoxFor(m=&gt; m.MyText)
  @Html.TextBoxFor(m=&gt; m.MyNumber)
  &lt;span&gt;@DateTime.Now.Second&lt;/span&gt;
  </code></pre>
  
  <p>My controller contains four actions: </p>
  
  <pre><code>[HttpGet]
  public ActionResult Index()
  {
      MyModel model = new MyModel();
      return View(model);
  }
  
  
  [HttpPost]
  public PartialViewResult Index(MyModel model)
  {
      if (model.MyNumber == 1)
      {
          return Cat(model);
      }
      else
      {
          return Dog(model);
      }
  }
  
  [HttpPost]
  public PartialViewResult Cat(MyModel model)
  {
      model.MyText = model.MyText + " K";
      return PartialView("Cat", model);
  }
  
  [HttpPost]
  public PartialViewResult Dog(MyModel model)
  {
      model.MyText = model.MyText + " P";
      return PartialView("Dog", model);
  }
  </code></pre>
  
  <p>My problem is that when Cat or Dog action is performed, MyText in model is changed, but when correct partial view is displayed I see old (not updated) MyText. Why?
  Any other ideas how to show a specific partial view depending on data posted in the form are welcome.</p>