public ActionResult AddFolder(AddFolderViewModel Model) { if (Pservice.CanUserOpenProject(Model.ProjectID, User.Identity.Name)) { if (ModelState.IsValid) { // We add the folder and redirect to the Editor. FoService.AddFolder(Model); return(RedirectToAction("Index", new { id = Model.ProjectID })); } else if (Model.Name == null) { return(Json("EmptyString", JsonRequestBehavior.AllowGet)); } } throw new ArgumentException(); }