public PartialViewResult _LoadDanhSachTheoSanPham(int?SanPhamId)
{
SanPhamService service = new SanPhamService();
ViewBag._LoadDanhSachSanPham = new SelectList(service.DSSanPham(), "SanPhamId", "TenSanPham", SanPhamId);
return(PartialView());
}