title: How to modify posted form data within controller action before sending to view?
body: <p>I want to render the same view after a successful action (rather than use RedirectToAction), but I need to modify the model data that is rendered to that view. The following is a contrived example that demonstrates two methods that that do not work:</p>
  
  <pre><code>    [AcceptVerbs("POST")]
      public ActionResult EditProduct(int id, [Bind(Include="UnitPrice, ProductName")]Product product) {
          NORTHWNDEntities entities = new NORTHWNDEntities();
  
          if (ModelState.IsValid) {
              var dbProduct = entities.ProductSet.First(p =&gt; p.ProductID == id);
              dbProduct.ProductName = product.ProductName;
              dbProduct.UnitPrice = product.UnitPrice;
              entities.SaveChanges();
          }
  
          /* Neither of these work */
          product.ProductName = "This has no effect";
          ViewData["ProductName"] = "This has no effect either";
  
          return View(product);
      }
  </code></pre>
  
  <p>Does anyone know what the correct method is for accomplishing this?</p>