public ActionResult AddPaymentByStudent(int?id, PaymentDetail paymentDetail) { if (ModelState.IsValid) { _paymentBl.InsertPaymentByStudent(paymentDetail); return(RedirectToAction("PaymentDetailsByStudent", "StudentInfoes", new { id = id })); } ViewBag.GradeId = new SelectList(_gradeBl.GetGrades(), "Id", "ClassName", paymentDetail.GradeId); ViewBag.StudentId = new SelectList(_studentBl.GetStudentInfos(), "Id", "Name", paymentDetail.StudentId); return(View(paymentDetail)); }