protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            LopHoc lh = new LopHoc();
            if (Request.QueryString["action"] == "nhapdiem")
            {
                string action = Request.QueryString["nhapdiem"];
                string malop  = Request.QueryString["malop"];
                Session["malop"] = malop;

                lh.MaLop = Session["malop"].ToString();
            }
            lh.MaLop = Session["malop"].ToString();
            GiaoVien gv   = new GiaoVien();
            int      magv = int.Parse(Session["magv"].ToString());
            monhoc  = gvDAL.GetMaMonHoc(magv, lh.MaLop);
            gv.MaGV = magv;
            DSHocSinh.DataSource = gvDAL.GetDanhSachHSLopNhapDiem(Session["malop"].ToString(), magv, monhoc);
            DSHocSinh.DataBind();
            kiemtratb();
        }
        lbTenLop.Text = gvDAL.LayTenLop(Session["malop"].ToString());
        lbMonHoc.Text = gvDAL.LayTenMonHoc(monhoc);
    }