public class CommonUtil
    {
        #region 微信相关帮助

        /// <summary>
        /// 生成指定长度的签名的随机串
        /// </summary>
        /// <param name="length"></param>
        /// <returns></returns>
        public static String CreateNoncestr(int length)
        {
            String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            String res = "";
            Random rd = new Random();
            for (int i = 0; i < length; i++)
            {
                res += chars[rd.Next(chars.Length - 1)];
            }
            return res;
        }

        /// <summary>
        /// 生成签名的随机串
        /// </summary>
        /// <returns></returns>
        public static String CreateNoncestr()
        {
            String chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            String res = "";
            Random rd = new Random();
            for (int i = 0; i < 16; i++)
            {
                res += chars[rd.Next(chars.Length - 1)];
            }
            return res;
        }

        /// <summary>
        /// 生成签名的时间戳
        /// </summary>
        /// <returns></returns>
        public static String CreateTimeStamp()
        {
            return ((DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000).ToString();
        }

        /// <summary>
        /// 获取微信JS接口的临时票据
        /// </summary>
        /// <param name="jsTicketUrl">js ticket url</param>
        /// <param name="accessToken">微信的accesstoken</param>
        /// <returns></returns>
        public static String CreateJsTicket(string jsTicketUrl, string accessToken)
        {
            string ticketUrl = string.Format(jsTicketUrl, accessToken);
            string result =WebHttpHelper.CreateWebrequest(ticketUrl);
            IHashObject obj = Carpa.Web.Ajax.JavaScriptSerializer.CreateInstance().DeserializeObject(result) as IHashObject;
            if (obj.Count > 0)
            {
                if (obj.GetValue("errcode", "").Equals("0"))
                {
                    return obj.GetValue("ticket", "");
                }
            }
            return "";
        }

        /// <summary>
        /// 生成 wx config签名；参与签名的参数如下(jsapi_ticket,noncestr,&timestamp,url-当前请求的url)
        /// </summary>
        /// <param name="dic"></param>
        /// <returns></returns>
        public static String CreateSignature(Dictionary<string, string> dic)
        {
            //字典排序
            var dictemp = dic.OrderBy(d => d.Key);
            #region 生成url字符串
            StringBuilder str = new StringBuilder();
            foreach (var item in dictemp)
            {
                str.AppendFormat("{0}={1}&", item.Key, item.Value);
            }
            #endregion
            var temp = str.ToString().Trim(‘&‘);
            return Util.Sha1(temp);
        }

        /// <summary>
        /// 网页授权认证获取用户的opneid
        /// </summary>
        /// <param name="url">授权地址</param>
        /// <param name="appId">appid</param>
        /// <param name="appKey">appid</param>
        /// <param name="code">授权获取的code</param>
        /// <returns></returns>
        public static String GetOpenIdByOauth(string url, string appId, string appKey, string code)
        {
            string aUrl = string.Format(url, appId, appKey, code);
            string result = WebHttpHelper.CreateWebrequest(aUrl);
            IHashObject obj = Carpa.Web.Ajax.JavaScriptSerializer.CreateInstance().DeserializeObject(result) as IHashObject;
            if (obj.Count > 0)
            {
                if (obj.GetValue("openid", "") != "")
                {
                    return obj.GetValue("openid", "");
                }
            }
            return "";
        }

        #endregion
    }