protected void ddTP_SelectedIndexChanged(object sender, EventArgs e)
{
XemDSKho.Visible = true;
int masp = int.Parse(ddTP.SelectedValue);
DAO_Entity daoKH = new DAO_Entity();
DTOSanPhamCT dtosp = daoKH.LayGiaSPTheoMaCT(masp);
lbgia.Text = dtosp.Gia.ToString();
int ma = int.Parse(ddTP.SelectedValue);
DAO_Entity dao = new DAO_Entity();
DTOKhoSP dto = dao.LaySoLuongKhoSP(ma);
lbSLKho.Text = dto.Soluong.ToString();
}