// The id parameter should match the DataKeyNames value set on the control // or be decorated with a value provider attribute, e.g. [QueryString]int id public SAN_PHAM SanPhamDetail_GetItem([QueryString("MaSP")] int id) { DB_SPAEntities context = new DB_SPAEntities(); sanPhamDAL sp = new sanPhamDAL(); var sp2 = sp.GetDVByMa(id); return(sp2); }