public ActionResult Delete(string key)
        {
            SystemSetting systemSetting = _systemSettingService.GetSystemSetting(key);

            if (systemSetting == null)
            {
                ErrorNotification("Không tìm thấy trang nào thỏa mãn");
                return(RedirectToAction("Index"));
            }
            _systemSettingService.RemoveSystemSetting(systemSetting);
            SuccessNotification("Xóa SystemSetting thành công");
            return(RedirectToAction("Index"));
        }