///验签绑定公众号的时候，有回复信息的入口
public void ProcessRequest(HttpContext context)
        {
            string postString = string.Empty;
            if (HttpContext.Current.Request.HttpMethod.ToUpper() == "POST")
            {
                using (Stream stream = HttpContext.Current.Request.InputStream)
                {
                    Byte[] postBytes = new Byte[stream.Length];
                    stream.Read(postBytes, 0, (Int32)stream.Length);
                    postString = Encoding.UTF8.GetString(postBytes);
                }

                if (!string.IsNullOrEmpty(postString))
                {
                    WeiXinService.ResponseMsg(postString, context);
                }
            }
            else
            {
                Auth(); //微信接入的测试
            }
        }

/// <summary>
        /// 处理回复消息
        /// </summary>
        /// <param name="postString"></param>
        /// <returns></returns>
        public void ResponseMsg(string postString, HttpContext context)
        {
    //通过信息类型返回相应的处理类
            IHandler handler = HandlerFactory.CreateHandler(postString);
            if (handler != null)
            {
                 handler.HandleRequest(context);
            }
        }

        /// <summary>
        /// 创建处理器
        /// </summary>
        /// <param name="requestXml">请求的xml</param>
        /// <returns>IHandler对象</returns>
        public static IHandler CreateHandler(string requestXml)
        {
            IHandler handler = null;
            if (!string.IsNullOrEmpty(requestXml))
            {
                //解析数据
                XmlDocument doc = new System.Xml.XmlDocument();
                doc.LoadXml(requestXml);
                XmlNode node = doc.SelectSingleNode("/xml/MsgType");
                if (node != null)
                {
                    XmlCDataSection section = node.FirstChild as XmlCDataSection;
                    if (section != null)
                    {
                        string msgType = section.Value;
                        //工厂类
                        switch (msgType)
                        {
                            case "text":
                                handler = new TextHandler(requestXml);
                                break;
                            case "event":
                                handler = new EventHandler(requestXml);
                                break;
                        }
                    }
                }
            }

            return handler;
        }

/// <summary>
        /// 事件处理，处理请求
        /// </summary>
        /// <returns></returns>
        public void HandleRequest(HttpContext context)
        {
            string response = string.Empty;
            EventMessage em = EventMessage.LoadFromXml(RequestXml);
            switch (em.Event.ToLower())
            {
                case ("unsubscribe")://取消关注
                    UnSubscribeEventHandler(em, context);
                    break;
                case ("subscribe"): //关注
                    SubscribeEventHandler(em, context);
                    break;
                case "click": //点击事件
                    ClickEventHandler(em, context);
                    break;
            }
        }

点击事件

/// <summary>
        /// 处理点击事件
        /// </summary>
        /// <param name="em"></param>
        /// <returns></returns>
        private void ClickEventHandler(EventMessage em, HttpContext context)
        {
            string result = string.Empty;
            if (em != null && em.EventKey != null)
            {
                switch (em.EventKey.ToUpper())
                {
                    case "BTN_HELP":
                        btnHelpClick(em, context);
                        break;
                    case "BTN_QRCODE":
                        btnQrcodeClick(em, context);
                        break;
                }
            }
        }

/// <summary>
        /// 
        /// </summary>
        /// <param name="em"></param>
        /// <returns></returns>
        private void btnHelpClick(EventMessage em, HttpContext context)
        {
            //回复欢迎消息
            TextMessage tm = new TextMessage();
            tm.ToUserName = em.FromUserName;
            tm.FromUserName = em.ToUserName;
            tm.CreateTime = WeiXinCommom.GetNowTime();
            tm.Content = “回复内容”;
            string response = TextTemplate.NormalText(tm.ToUserName, tm.FromUserName, tm.Content);
            context.Response.Clear();
            context.Response.Charset = "UTF-8";
            context.Response.Write(response);//回复消息
            context.Response.End();
        }