（利用tempdata判断action是直接被访问还是重定向访问）防止微信活动中用户绕过关注公众号的环节

 public ActionResult Topic_JieYuan()
        {
            int count = bllOrders.GetOrderCount();
            ViewData["count"] = count;
            if (Request["isweixin"] != null)  //表明是从微信过来的
            {
                TempData["isweixin"] = 1;
                return RedirectToAction("Topic_JieYuan", "topic", new { isfirst = 1 }); //进行重定向生成新的url，新url地址中有一个参数是isfirst =1与最原始的url不一样(用户分享的话是新的url)，当下次有人直接打开分享的地址时，由于TempData["isweixin"] = null所以不会运行 ViewData["isback"] = 1;这段(前台是根据 ViewData["isback"] = 1;来做一些权限判断显示的)
            }
            if (Request["isfirst"] != null && TempData["isweixin"] != null)
            {
                ViewData["isback"] = 1;
            }
           
            return View("/Views/Topic/JieYuan/topicjieyuan.aspx");
        }
//同上
  public ActionResult JieYuan() 
        {
            //if (!Request.Headers["User-Agent"].Contains("MicroMessenger"))
            //{
            //    Response.Redirect("/topic/jieyuan.htm");
            //    return View("/Views/Topic/JieYuan/topicjieyuan.aspx");
            //}

            if (Request["isback"] == null)
            {
                TempData["isweixin"] = 1;
                return RedirectToAction("JieYuan", "topic", new { isback = 1 });
                //Response.Redirect("/topic/jieyuan.htm?isweixin=1&isback=1");
                //return View("/Views/Topic/JieYuan/topicjieyuan.aspx");
            }
            if (TempData["isweixin"] == null)
            {
                return RedirectToAction("Topic_JieYuan", "topic");
            }

            Hashtable htRegion = new Hashtable();
            htRegion.Add("ParentId", 0);
            List<Jiyun.Model.Jy_Hishop_Regions> listRegion = bllOrders.GetRegionsList(htRegion);
            ViewData["list"] = listRegion;
            return View("/Views/Topic/JieYuan/Index.aspx");
        }