public ActionResult Seacrh(int?danhmuc, string TenSp, decimal?GiaNhap)
{
List <DanHMuc> dm = DanhMucMager.getAllDanhMuc();
ViewBag.danhmuc = new SelectList(dm, "MaDM", "TenDM");
List <SanPham> lstsp = SanPhamMager.GetSPbyDM(danhmuc);
List <SanPham> lstsp1 = SanPhamMager.GetSPbytensp(TenSp);
lstsp.AddRange(lstsp1);
List <SanPham> lstsp2 = SanPhamMager.GetSpByGiaNhap(GiaNhap);
lstsp.AddRange(lstsp2);
return(View("Index", lstsp));
}