public ActionResult Create(Student std) { if (!ModelState.IsValid) { return(View(std)); } if (std == null) { ModelState.AddModelError(string.Empty, "Student is NULL."); return(View(std)); } std.StudentName = std.StudentName.Trim(); // check whether name already exists in database. bool nameAlreadyExists = StudentDao.StudentNameExists(std.StudentName); if (nameAlreadyExists) { ModelState.AddModelError(string.Empty, "Student Name already exists."); return(View(std)); } // Update database. int i = StudentDao.InsertRecord(std); if (i == 1) { return(RedirectToAction("Index")); } else if (i < 1) { ModelState.AddModelError(string.Empty, "Fail to create it in database."); return(View(std)); } else { ModelState.AddModelError(string.Empty, "More than ONE record are created in database."); return(View(std)); } }