private void FillChildNode(string mavt, TreeNode topnode) { DataTable dt = nguoiDungBUS.LayDuLieuNguoiDung(string.Format("select ID, TenDangNhap, MaVaiTro from NGUOIDUNG where MaVaiTro = '{0}'", mavt)); foreach (DataRow row in dt.Rows) { NguoiDung nd = new NguoiDung(); nd.ID = int.Parse(row["ID"].ToString()); nd.TenDangNhap = row["TenDangNhap"].ToString(); nd.MaVaiTro = row["MaVaiTro"].ToString(); TreeNode tn = new TreeNode(nd.TenDangNhap); tn.Tag = nd; topnode.Nodes.Add(tn); } }