微信加关注不会自动发送消息，求大家帮忙看看

if (Request.HttpMethod.ToLower() == "post")
        {
            Stream s = System.Web.HttpContext.Current.Request.InputStream;
            byte[] b = new byte[s.Length];
            s.Read(b, 0, (int)s.Length);
            postStr = Encoding.UTF8.GetString(b);//postStr是xml内容

            if (!string.IsNullOrEmpty(postStr)) //请求处理
            {
                WeiXinMDL requestXML = new WeiXinMDL();
                requestXML = _wx.Handle(postStr); //对xml进行拆分，放入WeiXinMDL
                WeiXinBLL wxbll = new WeiXinBLL();
                wxbll.AppendInfor(requestXML); //用户提交的信息保存放数据库


               

                if (requestXML.MsgType == "text")
                {
                    WeiXin_contentBLL wx_contentbll = new WeiXin_contentBLL();
                    List<WeiXin_contentMDL> list = wx_contentbll.GetListInfor(" news_sort = '" + requestXML.Content + "' ");
                    if (list.Count > 0)
                    {
                        //string re_content = "";
                        List<WeiXinMDL> replyXML_list = new List<WeiXinMDL>();
                        foreach (WeiXin_contentMDL model in list)
                        {
                            WeiXinMDL replyXML = new WeiXinMDL();
                            if (model.nc_type == "text")
                            {
                                replyXML.Content = model.nc_newsSummary;
                                replyXML.ToUserName = requestXML.ToUserName;
                                replyXML.FromUserName = requestXML.FromUserName;
                                replyXML.MsgType = model.nc_type;//text表示回复文字内容，image表示回复图文件内容

                            }
                            else
                            {
                                replyXML.Title = model.nc_title;
                                replyXML.Description = model.nc_newsSummary;
                                replyXML.PicUrl = model.nc_title_pic;
                                replyXML.Url = model.nc_url;
                                replyXML.ToUserName = requestXML.ToUserName;
                                replyXML.FromUserName = requestXML.FromUserName;
                                replyXML.MsgType = model.nc_type;//text表示回复文字内容，image表示回复图文件内容
                            }
                            replyXML_list.Add(replyXML);
                        }



                        _wx.ResponseMsg(replyXML_list);
                    }
                }
                else if (requestXML.MsgType == "event")
                {

                    List<WeiXinMDL> replyXML_list = new List<WeiXinMDL>();
                    WeiXinMDL replyXML = new WeiXinMDL();
                    String eventType = (string)requestXML.Event1;
                    if (eventType == "subscribe")
                    {
                        replyXML.Content = "欢迎您的关注";
                        replyXML.ToUserName = requestXML.ToUserName;
                        replyXML.FromUserName = requestXML.FromUserName;
                        replyXML.MsgType = "text";//text表示回复文字内容，image表示回复图文件内容
                    }
                    replyXML_list.Add(replyXML);
                    _wx.ResponseMsg(replyXML_list);
                }


                
            }
        } 微信

补充：移动开发 ,  Android