title: Partial Views & ModelState.AddModelError
body: <p>the source of <code>LoginRegister</code> view is like this :</p>
  
  <pre><code>@Html.Partial("authentication/_login")
  @Html.Partial("authentication/_register")
  </code></pre>
  
  <p>and each child view has got a form with this syntax </p>
  
  <pre><code>@using (Html.BeginForm(**seperated-methods**, "Login")) 
  {
      @Html.ValidationSummary(false)
  } 
  </code></pre>
  
  <p>I send error(s) in postback whit this code</p>
  
  <pre><code>ModelState.AddModelError("", "**any-error-message**");
  return View("authentication/LoginRegister", customized-data);
  </code></pre>
  
  <p>The point is , error message shows in both <code>partial views</code>.</p>