title: Get error message if ModelState.IsValid fails?
body: <p>I have this function in my controller.</p>
  
  <pre><code>[HttpPost]
  public ActionResult Edit(EmployeesViewModel viewModel)
  {
      Employee employee = GetEmployee(viewModel.EmployeeId);
      TryUpdateModel(employee);
  
      if (ModelState.IsValid)
      {
          SaveEmployee(employee);
          TempData["message"] = "Employee has been saved.";
          return RedirectToAction("Details", new { id = employee.EmployeeID });
      }
  
      return View(viewModel); // validation error, so redisplay same view
  }
  </code></pre>
  
  <p>It keeps failing, <code>ModelState.IsValid</code> keeps returning false and redisplaying the view. But I have no idea what the error is.</p>
  
  <p>Is there a way to get the error and redisplay it to the user?</p>