一、 第一种帮助形式

        /// <summary>
        /// 响应文本消息
        /// </summary>
        /// <param name="xml"></param>
        /// <returns></returns>
        private string OnReceiveTextMsg(string xml)
        {
            WxTextMsg msg = XmlEntityExchange<WxTextMsg>.ConvertXml2Entity(xml);
            //返回消息，互换收发用户
            string toUser = msg.FromUserName;
            msg.FromUserName = msg.ToUserName;
            msg.ToUserName = toUser;

            switch (msg.Content.Trim())
            {
                case "?":
                    msg.Content = HelpDocument();
                    break;
                case "？":
                    msg.Content = HelpDocument();
                    break;
                case "1":
                    msg.Content = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");
                    break;
                case "2":
                    msg.Content = Tools.HttpCrossDomain.Get("http://www.weather.com.cn/data/sk/101210301.html");
                    break;
                case "3":
                    msg.Content = "来吧，想唠点什么呢？ [偷笑]";
                    break;
                case "你是男的女的":
                    msg.Content = "姑娘一枚 [偷笑]";
                    break;
                default:
                    msg.Content = "抱歉哦，我不认识您输入的命令。/害羞 /:,@-D";
                    break;
            }
            return XmlEntityExchange<WxTextMsg>.ConvertEntity2Xml(msg);
        }
        /// <summary>
        /// 获取帮助菜单文档
        /// </summary>
        /// <returns></returns>
        private string HelpDocument()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("HI，请回复数字，选择服务").Append("\n\n");
            sb.Append("1. 当前时间").Append("\n");
            sb.Append("2. 天气信息").Append("\n");
            sb.Append("3. 聊天唠嗑").Append("\n");
            sb.Append("n. 更多服务开发中...").Append("\n");
            sb.Append("回复【?】显示此帮助菜单");
            return sb.ToString();
        }

二、第二种帮助形式

public static class ReadXml
    {

        //输出字符串并结束当前页面进程 MVC必须加return
        public static string  Menu()
        {
            string Content = "";
            Content += "欢迎使用XXXX/微笑\n\n";
            Content += "输入以下序号开始获取最新信息：\n";
           
            Content += "1,新闻30分\n";
            Content += "2,电影预告\n";
            Content += "3,今日说法\n";
            Content += "4,焦点访谈\n";
            Content += "5,新闻联播\n";

            Content += "输入?或帮助 可以显示此菜单";
            return Content;
        }

    }

if (text == "?" || text == "？" || text == "帮助")
           {
               mT.Content =  ReadXml.Menu();
           }

微信自动回复时最好能够提供帮助信息