Update the model on HttpPost and render the changes in the View
- by Etienne Giust
With MVC3, I came over that problem where I was rendering a view with an updated model at the end of an HttpPost and the changes to the model were never applied to the rendered view : NOT working as expected ! [HttpPost] public ActionResult Edit(JobModel editedJobModel) { // Update some model property editedJobModel.IsActive = true; // The view will NOT be updated as expected return View(editedJobModel); } This is the standard behavior. In MVC3, POSTing the model does not render the Html helpers again. In my example, a HiddenFor bound to the IsActive value will not have its value set to true after the view is rendered. Are you stuck, then ? Well, for one, you’re not supposed to do that: in an ideal world you are supposed to apply the Post/Redirect/Get pattern. You would redirect to a new GET after your POST performed its actions. That’s what I usually do, but sometimes, when maintaining code and implementing slight changes to a pre-existing and tested logic, one prefers to keep structural changes to a minimum. If you really have to (but my advice is to try to implement the PRG pattern whenever possible), here is a solution to alter values of the model on a POST and have the MVC engine render it correctly : Solution [HttpPost] public ActionResult Edit(JobModel editedJobModel) { // NOT WORKING : Update some model property //editedJobModel.IsActive = true; //Force ModelState value for IsActive property ModelState["IsActive"].Value = new ValueProviderResult(true, "True", null); // The view will be updated as expected return View(editedJobModel); } As you can see, it is a “dirty” solution, as the name (as a string) of the updated property is used as a key of the ModelState dictionary. Also, the use of ValueProviderResult is not that straightforward. But hey, it works.
