protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
{
string maSach = GridView1.SelectedRow.Cells[0].Text;
s = cn.GetSachByID(maSach);
if (s != null)
{
txtMaSach.Text = s.MaSach;
txtTenSach.Text = s.TenSach;
ddlNhaXuatBan.SelectedValue = s.MaNhaXuatBan;
txtMoTa.Text = s.MoTa;
ddlLoaiSach.SelectedValue = s.MaLoai;
ddlTacGia.SelectedValue = s.MaTacGia;
txtSoLuong.Text = s.SoLuong.ToString();
}
}