public ActionResult Edit(int id = 0, string error = "")
        {
            Banner banner = new Banner();
            banner.ID = id;
            if (id > 0) {
                banner.Get();
            }
            if (TempData["banner"] != null) {
                try {
                    banner = (Banner)TempData["banner"];
                } catch (Exception) { }
            }
            ViewBag.banner = banner;
            ViewBag.banner_count = banner.GetAll().Count;

            ViewBag.error = error;
            return View();
        }