public ActionResult ChangeFileName(int ProjectID, int FileID, string NewName) { // If the user can open the project he can also change file names. if (Pservice.CanUserOpenProject(ProjectID, User.Identity.Name)) { // If the we get the file that was changed we return it. var FileChanged = FService.ChangeFileName(ProjectID, FileID, NewName); if (FileChanged != null) { return(Json(FileChanged, JsonRequestBehavior.AllowGet)); } else { // If we don't get the file we return this to JavaScript code // for error handling. return(Json("SameName", JsonRequestBehavior.AllowGet)); } } throw new ArgumentException();; }