partial void DeleteSanPham(SanPham instance);
 partial void UpdateSanPham(SanPham instance);
 private void detach_SanPhams(SanPham entity)
 {
     this.SendPropertyChanging();
     entity.LoaiSanPham = null;
 }
 partial void InsertSanPham(SanPham instance);
 private void attach_SanPhams(SanPham entity)
 {
     this.SendPropertyChanging();
     entity.LoaiSanPham = this;
 }