public ActionResult UpdateStudent(StudentUpdateModel model, int? id)
        {

            var hallId = 0;
            var selectedHallId = 0;
            if (ModelState.IsValid)
            {

                var si = _db.StudentInformations.Find(id);
                if (model.HallName != null)
                {
                    hallId = Convert.ToInt32(model.HallName);
                    si.HallId = hallId;
                }
                si.Phone = model.Phone;
                si.Email = model.Email;


                si.PresentAddress = model.PresentAddress;

                _db.Entry(si).State = EntityState.Modified;
                _db.SaveChanges();
                return RedirectToAction("DisplayAdminHomePage");

            }




            ViewBag.halls = _db.Halls.Select(m => m.HallName).ToList();
            var supm = new StudentUpdateModel();
            var information = _db.StudentInformations.Find(id);

            supm.PresentAddress = information.PresentAddress;
            supm.Phone = information.Phone;
            supm.Email = information.Email;
            supm.Image = information.StudentImage;

            if (model.HallName != "")
            {

                selectedHallId = hallId;
                ViewBag.hallListShowId = 1;
            }

            var halls = _db.Halls.Select(c => new
            {
                HallId = c.Id,

                Hall = c.HallName
            }).ToList();

            var selectList = new SelectList(halls, "HallId", "Hall", selectedHallId);

            ViewData["Halls"] = selectList;


            return PartialView("_UpdateStudent", supm);
        }
        public ActionResult UpdateStudent(int id)
        {
            if (Request.IsAjaxRequest())
            {
                var hallName = "";

                ViewBag.halls = _db.Halls.Select(m => m.HallName).ToList();
                var supm = new StudentUpdateModel();
                var u = _db.StudentInformations.SingleOrDefault(m => m.Id.Equals(id));

                var hallId = u.HallId;
                var n = _db.Halls.SingleOrDefault(c => c.Id.Equals(hallId.Value));
                if (n != null)
                    hallName = n.HallName;
                if (hallName != "")
                {
                    ViewBag.hallListShowId = 1;

                }


                var information = _db.StudentInformations.Find(id);

                supm.PresentAddress = information.PresentAddress;
                supm.Phone = information.Phone;
                supm.Email = information.Email;
                supm.Image = information.StudentImage;

                var halls = _db.Halls.Select(c => new
                {
                    HallId = c.Id,

                    Hall = c.HallName
                }).ToList();


                var h = _db.Halls.FirstOrDefault(m => m.HallName.Equals(hallName));
                SelectList selectList;
                if (u.HallId > 0)
                {
                    selectList = h != null ? new SelectList(halls, "HallId", "Hall", h.Id) : new SelectList(halls, "HallId", "HallName");

                }
                else
                {
                    selectList = new SelectList(halls, "HallId", "Hall");
                }

                ViewData["Halls"] = selectList;


                return PartialView("_UpdateStudent", supm);
            }
            else
            {
                return View("ProcessingError");
            }




        }