protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
string maLoai = GridView1.SelectedRow.Cells[0].Text;
ls = cn.GetLoaiSachByID(maLoai);
if (ls != null)
{
txtMaLoaiSach.Text = ls.MaLoai;
txtTenLoaiSach.Text = ls.TenLoaiSach;
}
}
