//跳转微信登录页面
public ActionResult Index()
{
 ViewBag.url = "https://open.weixin.qq.com/connect/oauth2/authorize" + {服务号appid} + "&redirect_uri=http%3A%2F%2F" + {微信重定向域名(填写程序域名,例如:www.xxxx.com)} + "%2F"+{程序控制器名,例如:Home}+"%2F"+{程序Action名,例如:RedirectWeChat}+"&response_type=code&scope=snsapi_userinfo&state=STATE#wechat_redirect";
 return View();
}

//获取accesstoken(访问微信接口需要)
public static string accesstoken(string WeChatWxAppId, string WeChatWxAppSecret)
{
 string strJson = HttpRequestUtil.RequestUrl(string.Format("https://api.weixin.qq.com/cgi-bin/token", WeChatWxAppId, WeChatWxAppSecret));
 if (strJson.IndexOf("errcode") == -1)
 {
  return GetJsonValue(strJson, "access_token");
 }
 else
 {
  return "";
 }
}
//解析json
public static string GetJsonValue(string jsonStr, string key)
{
 string result = string.Empty;
 if (!string.IsNullOrEmpty(jsonStr))
 {
  key = "\"" + key.Trim('"') + "\"";
  int index = jsonStr.IndexOf(key) + key.Length + 1;
  if (index > key.Length + 1)
  {
   //先截逗号，若是最后一个，截“｝”号，取最小值
   int end = jsonStr.IndexOf(',', index);
   if (end == -1)
   {
    end = jsonStr.IndexOf('}', index);
   }
   result = jsonStr.Substring(index, end - index);
   result = result.Trim(new char[] { '"', ' ', '\'' }); //过滤引号或空格
  }
 }
 return result;
}

//请求url
public static string RequestUrl(string url, string method="post")
{
 // 设置参数
 HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
 CookieContainer cookieContainer = new CookieContainer();
 request.CookieContainer = cookieContainer;
 request.AllowAutoRedirect = true;
 request.Method = method;
 request.ContentType = "text/html";
 request.Headers.Add("charset", "utf-8");
 //发送请求并获取相应回应数据
 HttpWebResponse response = request.GetResponse() as HttpWebResponse;
 //直到request.GetResponse()程序才开始向目标网页发送Post请求
 Stream responseStream = response.GetResponseStream();
 StreamReader sr = new StreamReader(responseStream, Encoding.UTF8);
 //返回结果网页（html）代码
 string content = sr.ReadToEnd();
 return content;
}
//接收微信返回code
//接收微信数据获取用户信息
public ActionResult RedirectWeChat(string code, string state)
{
 if (string.IsNullOrEmpty(code))
 {
  return Content("您拒绝了授权！");
 }
 string access_token = accesstoken(微信AppId, 微信AppSecret);
 string st = "https://api.weixin.qq.com/sns/oauth2/access_token" + 微信AppId + "&secret=" + 微信AppSecret + "&code=" + code + "&grant_type=authorization_code";
 string data = RequestUrl(st);
//拿到用户openid
string openid=GetJsonValue(data, "openid");
//获取用户其他信息
 string url = "https://api.weixin.qq.com/cgi-bin/user/info" + access_token + "&openid=" + openid + "&lang=zh_CN";
 data = RequestUrl(url);
string subscribe=GetJsonValue(data, "subscribe");
 if (subscribe == "0")
 {
  ///未关注
  return RedirectToAction("");
 }

 return RedirectToAction("");
}

//发送红包Action
public ActionResult HB()
{
 string openid = "";//用户openid
 string url = "https://api.mch.weixin.qq.com/mmpaymkttransfers/sendredpack"; 
 string orderNo = 商户号 + DateTime.Now.ToString("yyyymmdd")+"随机10位数字";//商户订单号 组成：mch_id+yyyymmdd+10位一天内不能重复的数字。 
 string Code = ""//32为随机字符串; string key="key=" + "";//支付密钥(在商户平台设置32为字符串) 
 Dictionary<string, string> data = new Dictionary<string, string>(); data.Add("act_name", "");//活动名称 
 data.Add("client_ip", "192.168.1.1");//Ip地址 
 data.Add("mch_billno", orderNo);//商户订单号 组成：mch_id+yyyymmdd+10位一天内不能重复的数字。 
 data.Add("mch_id", "");//商户号 
 data.Add("nonce_str", Code);//随机字符串 
 data.Add("re_openid", openid);//用户openid 
 data.Add("remark", "");//备注 
 data.Add("send_name","");//商户名称 
 data.Add("total_amount", "100");//付款金额 单位分 
 data.Add("total_num", "1");//红包发放总人数 
 data.Add("wishing", "恭喜发财");//红包祝福语 
 data.Add("wxappid", );//公众账号appid 
 string xml = GetXML(data, key);//签名+拼接xml 
 string str=PostWebRequests(url, xml);//微信返回xml err_code=SUCCESS 就是成功
 return View(""); 
}

//发送红包(MD5签名+拼接XML)
public static string GetXML(Dictionary<string, string> data,string paykey)
{
 string retStr;
 MD5CryptoServiceProvider m5 = new MD5CryptoServiceProvider();

 var data1=from d in data orderby d.Key select d;
 string data2 = "";
 string XML = "<xml>";
 foreach (var item in data1)
 {
  //空值不参与签名
  if (item.Value + "" != "")
  {
   data2 += item.Key +"="+ item.Value + "&";
  }
  XML += "<" + item.Key + ">" + item.Value+""+ "</" + item.Key + ">";
 }

 data2 += paykey;
 //创建md5对象
 byte[] inputBye;
 byte[] outputBye;

 //使用GB2312编码方式把字符串转化为字节数组．
 try
 {
  inputBye = Encoding.UTF8.GetBytes(data2);
 }
 catch
 {
  inputBye = Encoding.GetEncoding("GB2312").GetBytes(data2);
 }
 outputBye = m5.ComputeHash(inputBye);

 retStr = System.BitConverter.ToString(outputBye);
 retStr = retStr.Replace("-", "").ToUpper();
 XML += "<sign>" + retStr + "</sign>";//签名
 XML += "</xml>";
 return XML;
}

//发送红包请求Post方法
public static string PostWebRequests(string postUrl, string menuInfo)
{
 string returnValue = string.Empty;
 try
 {
  Encoding encoding = Encoding.UTF8;
  byte[] bytes = encoding.GetBytes(menuInfo);
  string cert = @"E:\cdcert\apiclient_cert.p12";//支付证书路径
  string password = "1212121";//支付证书密码

  ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult);
  X509Certificate cer = new X509Certificate(cert, password, X509KeyStorageFlags.MachineKeySet);
  HttpWebRequest webrequest = (HttpWebRequest)HttpWebRequest.Create(postUrl);
  webrequest.ClientCertificates.Add(cer);
  webrequest.Method = "post";
  webrequest.ContentLength = bytes.Length;
  webrequest.GetRequestStream().Write(bytes, 0, bytes.Length);
  HttpWebResponse webreponse = (HttpWebResponse)webrequest.GetResponse();
  Stream stream = webreponse.GetResponseStream();
  string resp = string.Empty;
  using (StreamReader reader = new StreamReader(stream))
  {
    return reader.ReadToEnd();
  }

 }
 catch (Exception ex)
 {
  return "";
 }
}