public ActionResult TaoLich(LichNop lichNop)
        {
            if (ModelState.IsValid)
            {
                try
                {
                    string[] ds      = (string[])Session["dsgv"];
                    var      session = (TaiKhoan)Session[ComMon.ComMonStants.UserLogin];
                    if (ds.Length > 1)
                    {
                        lichNop.TrangThai = true;
                        lichNop.xoa       = true;
                        lichNop.MaBoMON   = session.TaiKhoan1;
                        TracNghiemOnlineDB db = new TracNghiemOnlineDB();
                        db.LichNops.Add(lichNop);
                        db.SaveChanges();

                        for (int i = 0; i < ds.Length - 1; i++)
                        {
                            DSGV_ThucHien GV = new DSGV_ThucHien();
                            GV.MaGV   = ds[i];
                            GV.MaLich = new TracNghiemOnlineDB().LichNops.ToList().Last().id;
                            db.DSGV_ThucHien.Add(GV);
                            db.SaveChanges();
                        }
                        return(RedirectToAction("BoMON"));
                    }
                }
                catch {
                    ModelState.AddModelError("", "Vui lòng chọn giáo viên ");
                }
            }

            return(View(lichNop));
        }
        public ActionResult Updatebomon(LichNop lichNop)
        {
            if (ModelState.IsValid)
            {
                try
                {
                    string[] ds      = (string[])Session["dsgv"];
                    var      session = (TaiKhoan)Session[ComMon.ComMonStants.UserLogin];
                    if (ds.Length > 1)
                    {
                        TracNghiemOnlineDB db = new TracNghiemOnlineDB();
                        var lich = db.LichNops.Find(lichNop.id);
                        lich.NoiDung  = lichNop.NoiDung;
                        lich.ThoiGian = lichNop.ThoiGian;
                        lich.MaMon    = lichNop.MaMon;
                        db.SaveChanges();
                        var list = db.DSGV_ThucHien.Where(x => x.MaLich == lichNop.id).ToList();
                        foreach (var item in list)
                        {
                            db.DSGV_ThucHien.Remove(item);
                            db.SaveChanges();
                        }

                        for (int i = 0; i < ds.Length - 1; i++)
                        {
                            DSGV_ThucHien GV = new DSGV_ThucHien();
                            GV.MaGV   = ds[i];
                            GV.MaLich = lichNop.id;
                            db.DSGV_ThucHien.Add(GV);
                            db.SaveChanges();
                        }
                        return(RedirectToAction("BoMON"));
                    }
                }
                catch
                {
                    ModelState.AddModelError("", "Vui lòng chọn giáo viên ");
                }
            }
            return(View(lichNop));
        }