string CreateMaHocSinhMoi()
        {
            DShocsinhBLL dshsbll = new DShocsinhBLL();
            string       maHSMax = dshsbll.GetMaHSMax();

            return((Int32.Parse(maHSMax) + 1).ToString());
        }
        private void ThemSuaHocSinh_Load(object sender, EventArgs e)
        {
            List <string> listGioiTinh = new List <string>()
            {
                "Nam",
                "Nữ"
            };

            cbGioiTinh.DataSource = listGioiTinh;

            //neu day la tem moi hoc sinh thi minh se load san tbMaHocSinh bang gia tri moi
            if (this.tenHocSinh == null)
            {
                DShocsinhBLL dshsbll      = new DShocsinhBLL();
                string       maHocSinhMax = dshsbll.GetMaHSMax();

                tbMaHS.Text = (Int32.Parse(maHocSinhMax) + 1) + "";
            }
        }