public ActionResult DetailProduct(string id)
{
var p = new ProductDao();
var t = new AuthorDao();
var l = new TheLoaiDao();
var sanpham = p.GetSanPhamById(id);
ViewBag.RelatedProduct = p.GetLoaiSachByIDTacGia(sanpham.MaTacGia);
ViewBag.TacGia = t.GetTacgiaByIDTacgia(sanpham.MaTacGia);
ViewBag.LoaiSach = l.GetLoaiSachByMaLoaiSach(sanpham.MaLoaiSach);
return(View(sanpham));
}