.net开发微信公众平台的方法

const string Token = "aka";//定义一个局部变量不可以被修改，这里定义的变量要与接口配置信息中填写的Token一致
protected void Page_Load(object sender, EventArgs e)
{
        string postStr = "";
        Valid();//校验签名,当填入的信息提交之后页面有提示“你已成功成为公众平台开发者，可以使用公众平台的开发功能”这个的时候，接下来你就需要注释掉这个校验的方法，使得后面的消息回复得以正常运作
        if (Request.HttpMethod.ToLower() == "post")//当普通微信用户向公众账号发消息时，微信服务器将POST该消息到填写的URL上
        {
            postStr = PostInput();
            if (string.IsNullOrEmpty(postStr) == false)
            {
                //WriteLog(postStr,Server);//计入日记
                ResponseMsg(postStr);
            }
        }
}
private void Valid()
{
        string echoStr = Request.QueryString["echoStr"].ToString();
        if (CheckSignature())
        {
            if (!string.IsNullOrEmpty(echoStr))
            {
                Response.Write(echoStr);
                Response.End();
            }
        }
}

/// <summary>
/// 验证微信签名
/// </summary>
/// <returns></returns>
private bool CheckSignature()
{
        string signature = Request.QueryString["signature"].ToString();
        string timestamp = Request.QueryString["timestamp"].ToString();
        string nonce = Request.QueryString["nonce"].ToString();
        string[] ArrTmp = { Token, timestamp, nonce };
        Array.Sort(ArrTmp);//字典排序
        string tmpStr = string.Join("", ArrTmp);
        tmpStr = FormsAuthentication.HashPasswordForStoringInConfigFile(tmpStr, "SHA1");//对该字符串进行sha1加密
        tmpStr = tmpStr.ToLower();//对字符串中的字母部分进行小写转换，非字母字符不作处理
        //WriteLog(tmpStr, Server);//计入日志
        if (tmpStr == signature)//开发者获得加密后的字符串可与signature对比，标识该请求来源于微信。开发者通过检验signature对请求进行校验，若确认此次GET请求来自微信服务器，请原样返回echostr参数内容，则接入生效，否则接入失败
        {
            return true;
        }
        else
            return false;
}
/// <summary>
/// 获取post返回来的数据
/// </summary>
/// <returns></returns>
private string PostInput()
{
        Stream s = System.Web.HttpContext.Current.Request.InputStream;
        byte[] b = new byte[s.Length];
        s.Read(b, 0, (int)s.Length);
        return Encoding.UTF8.GetString(b);
}
/// <summary>
///返回微信信息结果
/// </summary>
/// <param name="weixinXML"></param>
private void ResponseMsg(string weixinXML)
{
        try
        {
            XmlDocument doc = new XmlDocument();
            doc.LoadXml(weixinXML);//读取XML字符串
            XmlElement rootElement = doc.DocumentElement;
            XmlNode MsgType = rootElement.SelectSingleNode("MsgType");//获取字符串中的消息类型
            string resxml = "";
            if (MsgType.InnerText == "text")//如果消息类型为文本消息
            {
                var model = new
                {
                    ToUserName = rootElement.SelectSingleNode("ToUserName").InnerText,
                    FromUserName = rootElement.SelectSingleNode("FromUserName").InnerText,
                    CreateTime = rootElement.SelectSingleNode("CreateTime").InnerText,
                    MsgType = MsgType.InnerText,
                    Content = rootElement.SelectSingleNode("Content").InnerText,
                    MsgId = rootElement.SelectSingleNode("MsgId").InnerText
                };
                resxml += "<xml><ToUserName><![CDATA[" + model.FromUserName + "]]></ToUserName><FromUserName><![CDATA[" + model.ToUserName + "]]></FromUserName><CreateTime>" + ConvertDateTimeInt(DateTime.Now) + "</CreateTime>";
                if (!string.IsNullOrEmpty(model.Content))//如果接收到消息
                {
                    if (model.Content.Contains(" 你好") || model.Content.Contains(" 好") || model.Content.Contains("hi") || model.Content.Contains("hello"))// 你好
                    {
                        resxml += "<MsgType><![CDATA[text]]></MsgType><Content><![CDATA[你好，有事请留言，偶会及时回复你的。]]></Content><FuncFlag>0</FuncFlag></xml>";
                    }
                 }
                 else//没有接收到消息
                {
                 resxml += "<MsgType><![CDATA[text]]></MsgType><Content><![CDATA[亲，感谢您对我的关注，有事请留言。]]></Content><FuncFlag>0</FuncFlag></xml>";
                }
                Response.Write(resxml);
            }
            if (MsgType.InnerText == "image")//如果消息类型为图片消息
            {
                var model = new
                {
                    ToUserName = rootElement.SelectSingleNode("ToUserName").InnerText,
                    FromUserName = rootElement.SelectSingleNode("FromUserName").InnerText,
                    CreateTime = rootElement.SelectSingleNode("CreateTime").InnerText,
                    MsgType = MsgType.InnerText,
                    PicUrl = rootElement.SelectSingleNode("PicUrl").InnerText,
                    MsgId = rootElement.SelectSingleNode("MsgId").InnerText
                };
                    resxml += "<xml><ToUserName><![CDATA[" + model.FromUserName + "]]></ToUserName><FromUserName>
                    <![CDATA[" + model.ToUserName + "]]></FromUserName>
                    <CreateTime>" + ConvertDateTimeInt(DateTime.Now) + "</CreateTime>
                    <MsgType><![CDATA[news]]></MsgType><ArticleCount>1</ArticleCount><Articles><item>
                    <Title><![CDATA[欢迎您的光临！]]></Title><Description><![CDATA[非常感谢您的关注！]]>
                    </Description><PicUrl><![CDATA[http://...jpg]]></PicUrl><Url><![CDATA[http://www.baidu.com/]]></Url></item></Articles><FuncFlag>0</FuncFlag></xml>";
                    Response.Write(resxml);
                        }
                        else//如果是其余的消息类型
                        {
                            var model = new
                            {
                                ToUserName = rootElement.SelectSingleNode("ToUserName").InnerText,
                                FromUserName = rootElement.SelectSingleNode("FromUserName").InnerText,
                                CreateTime = rootElement.SelectSingleNode("CreateTime").InnerText,
                            };
                         resxml += "<xml><ToUserName><![CDATA[" + model.FromUserName + "]]></ToUserName>
                         <FromUserName><![CDATA[" + model.ToUserName + "]]></FromUserName>
                         <CreateTime>" + ConvertDateTimeInt(DateTime.Now) + "</CreateTime>
                         <MsgType><![CDATA[text]]></MsgType><Content>
                         <![CDATA[亲，感谢您对我的关注，有事请留言，我会及时回复你的哦。]]></Content>
                         <FuncFlag>0</FuncFlag></xml>";    
                       Response.Write(resxml);
                            }
                        }
                        catch (Exception ex)
                        {
                            throw ex;
                        }
                        Response.End();
                }
/// <summary>
/// datetime转换成unixtime
/// </summary>
/// <param name="time"></param>
/// <returns></returns>
private int ConvertDateTimeInt(System.DateTime time)
{
        System.DateTime startTime = TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1));
        return (int)(time - startTime).TotalSeconds;
}
/// <summary>
/// 写日志(用于跟踪)，可以将想打印出的内容计入一个文本文件里面，便于测试
/// </summary>
public static void WriteLog(string strMemo, HttpServerUtility server)
{
        string filename = server.MapPath("/logs/log.txt");//在网站项目中建立一个文件夹命名logs（然后在文件夹中随便建立一个web页面文件，避免网站在发布到服务器之后看不到预定文件）
        if (!Directory.Exists(server.MapPath("//logs//")))
            Directory.CreateDirectory("//logs//");
        StreamWriter sr = null;
        try
        {
            if (!File.Exists(filename))
            {
                sr = File.CreateText(filename);
            }
            else
            {
                sr = File.AppendText(filename);
            }
            sr.WriteLine(strMemo);
        }
        catch
        {
        }
        finally
        {
            if (sr != null)
                sr.Close();
        }
}