title: Easy way to check for view model changes in asp.mvc
body: <p>Is there a easy way of checking a view model(Not Domain Model) for modifications in the post back?</p>
  
  <pre><code>    public ActionResult Billing()
      {
          var viewModel = new BillingViewModel();
  
          viewModel.prop1 = DomainService.Prop1 // Map Domain model to View Model
  
          return View(viewModel);
      }
  
      [AcceptVerbs(HttpVerbs.Post)]
      public ActionResult Billing(BillingViewModel viewModel)
      {
          //TODO: Check if ViewModel has changes and save to Domain Repository if valid
          if (ValidateBillingViewModel(viewModel))
          {
  </code></pre>
  
  <p>My homebrew solution would be to store a hash of model in hidden field and check it again, but is there a better option?             </p>