public void ProcessRequest(HttpContext context)
    {
        Response.ContentType = "text/plain";
        if (Request.HttpMethod.ToLower() == "post")
        {//消息处理
            using (StreamReader streamReader = new StreamReader(Request.InputStream, Encoding.UTF8))
            {
                var postString = streamReader.ReadToEnd();
                MessageHelper messageHelper = new MessageHelper();
                var responseContent = messageHelper.ResponseContent(postString);
                Response.ContentEncoding = Encoding.UTF8;
                Response.Write(responseContent);
            }
        }
        else
        {//验证服务
            var signature = Request.QueryString["signature"];
            var timestamp = Request.QueryString["timestamp"];
            var nonce = Request.QueryString["nonce"];
            var echostr = Request.QueryString["echostr"];
            var res = WeChatHelper.Check(signature, timestamp, nonce) ? echostr : "Verification passed";
            Response.Write(res);
            Response.End();
        }
    }

/// <summary>
    /// 校验signature
    /// </summary>
    /// <param name="signature"></param>
    /// <param name="token"></param>
    /// <param name="timestamp"></param>
    /// <param name="nonce"></param>
    /// <returns></returns>
    public static bool Check(string signature, string timestamp, string nonce)
    {
        string token = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
        var sha1 = GetSHA1(String.Join("", new[] { token, timestamp, nonce }.OrderBy(d => d).ToArray()));//.OrderBy(d => d)字典序
        return sha1 == signature;
    }

/// <summary>
/// 微信消息回复类
/// </summary>
public class MessageHelper
{
    /// <summary>
    /// 返回消息模板
    /// </summary>
    private string Message_Text { get { return @"<xml>
                            <ToUserName><![CDATA[{0}]]></ToUserName>
                            <FromUserName><![CDATA[{1}]]></FromUserName>
                            <CreateTime>{2}</CreateTime>
                            <MsgType><![CDATA[text]]></MsgType>
                            <Content><![CDATA[{3}]]></Content>
                            </xml>"; } }

    /// <summary>
    /// 多客服回复消息
    /// </summary>
    private string Message_Customer { get { return @"<xml>
                            <ToUserName><![CDATA[{0}]]></ToUserName>
                            <FromUserName><![CDATA[{1}]]></FromUserName>
                            <CreateTime>{2}</CreateTime>
                            <MsgType><![CDATA[transfer_customer_service]]></MsgType>
                            </xml>"; } }

    public string ResponseContent(string postStr)
    {
        XmlDocument xdoc = new XmlDocument();
        xdoc.LoadXml(postStr);
        var responseContent = "success";
        XmlNode MsgType = xdoc.SelectSingleNode("/xml/MsgType");
        if (MsgType != null)
        {
            switch (MsgType.InnerText)
            {
                case "event":
                    responseContent = EventHandle(xdoc);//事件处理
                    break;
                case "text":
                    responseContent = TextHandle(xdoc);//接受文本消息处理
                    break;
                default:
                    break;
            }
        }
        return responseContent;
    }

    private string EventHandle(XmlDocument xdoc)   //事件
    {
        var toUserName = xdoc.SelectNodes("/xml/ToUserName")[0].InnerText;//开发者微信公众号
        var openID = xdoc.SelectNodes("/xml/FromUserName")[0].InnerText;//微信用户唯一ID
        var eventType = xdoc.SelectNodes("/xml/Event")[0].InnerText;//事件
        var eventKey = xdoc.SelectNodes("/xml/EventKey")[0].InnerText;//事件Key
        var result = "";
        switch (eventType)
        {
            case "subscribe"://关注事件
                string welcomeContent = @"感谢您的关注！绑定xxx账号立刻获取现金！~~~ 如果您已经注册过xxx，请点击<a href=''http://www.baidu.com''>快速绑定</a>；如果您还不是我们的会员请点击<a href=''http://www.baidu.com''>立即注册</a>。";
                result = string.Format(Message_Text, openID, toUserName, ConvertDateTimeInt(DateTime.Now).ToString(), welcomeContent);
                break;
            case "click"://自定义点击事件
                switch (eventKey)
                {
                    case "LianXiKF":                        
                        if (DateTime.Now.Hour > 17 || DateTime.Now.Hour < 9)
                        {
                            string msg = "您好，感谢您的咨询，人工客服工作时间为 09:00 至 18:00。";
                            result = string.Format(Message_Text, openID, toUserName, ConvertDateTimeInt(DateTime.Now), msg);
                        }
                        else {
                            result = string.Format(Message_Customer, openID, toUserName, ConvertDateTimeInt(DateTime.Now));
                        }
                        break;
                    default: break;
                }
                break;
            default: break;
        }
        return result;
    }

    private string TextHandle(XmlDocument xdoc)  //文本信息
    {
        var res = "success";
        var content = xdoc.SelectNodes("/xml/Content")[0];
        var toUserName = xdoc.SelectNodes("/xml/ToUserName")[0].InnerText;//开发者微信公众号
        var openID = xdoc.SelectNodes("/xml/FromUserName")[0].InnerText;//微信用户唯一ID  
        if (content != null)
        {
            if (content.InnerText.Contains("您_好"))
            {
                res = string.Format(Message_Text, openID, toUserName, ConvertDateTimeInt(DateTime.Now), "嗨，您好！");
            }
        }
        return res;
    }

    /// <summary>
    /// 将时间转化为Unix时间戳
    /// </summary>
    /// <param name="time"></param>
    /// <returns></returns>
    private int ConvertDateTimeInt(DateTime time)
    {
        DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1));
        return (int)(time - startTime).TotalSeconds;
    }
}