public ActionResult Add(int ID)
{
GioHang giohang = GetCart();
ThuCung x = db.ThuCungs.Find(ID);
if (x == null)
{
return(View("Error"));
}
SanPham p = new SanPham(x.MaThuCung, x.TenThuCung, x.HinhAnh, (long)x.Gia, 1);
giohang.AddToCart(p);
return(RedirectToAction("Index"));
}