private void Update()
        {
            HocSinh hs = hocsinhDAP.getByID(itemID);

            hs.TEN      = Request["txtTen"].ToString();
            hs.NGAYSINH = Convert.ToDateTime(Request["dateNgaySinh"]);
            hs.GIOITINH = Convert.ToBoolean(Request["rdoGioiTinh"]);
            hs.QUEQUAN  = Request["txtQueQuan"].ToString();
            hs.LOPID    = Convert.ToInt32(Request["sltLop"]);

            hocsinhDAP.Save();
        }
        protected void Page_Load(object sender, EventArgs e)
        {
            QLSinhVienEntities dbContext  = new QLSinhVienEntities();
            HocSinhDAP         dapHocSinh = new HocSinhDAP(dbContext);
            LopHocDAP          dapLopHoc  = new LopHocDAP(dbContext);

            doAction = !string.IsNullOrEmpty(Request["do"]) ? Request["do"].ToString() : "";
            itemID   = !string.IsNullOrEmpty(Request["itemid"]) ? Convert.ToInt32(Request["itemid"]) : 0;
            if (itemID != 0)
            {
                hs = dapHocSinh.getByID(itemID);
            }
            tbl_lopHocs.AddRange(dapLopHoc.getData());
            tbl_HocSinhs.AddRange(dapHocSinh.getData());
        }