public readonly string Token = "哈哈哈";

//主方法

public string WXToken(string signature, string timestamp, string nonce, string echostr)

        {

            string EchoStr = Valid(signature, timestamp, nonce, echostr);

            if (!string.IsNullOrEmpty(EchoStr))

            {

                return echostr;

            }

            else

            {

                return "失败";

            }

        }

    /// <summary>

        /// 转Sha1

        /// </summary>

        /// <param name="pwd"></param>

        /// <returns></returns>

        public static string GetSHA1(string pwd)

        {

            SHA1 algorithm = SHA1.Create();

            byte[] data = algorithm.ComputeHash(Encoding.UTF8.GetBytes(pwd));

            string sh1 = "";

            for (int i = 0; i < data.Length; i++)

            {

                sh1 += data[i].ToString("x2").ToUpperInvariant();

            }

            return sh1;

        }

 /// <summary>

        /// 对比

        /// </summary>

        /// <param name="signature"></param>

        /// <param name="timestamp"></param>

        /// <param name="nonce"></param>

        /// <param name="echostr"></param>

        /// <returns></returns>

        private string Valid(string signature, string timestamp, string nonce, string echostr)

        {

            if (CheckSignature(signature, timestamp, nonce))

            {

                if (!string.IsNullOrEmpty(echostr))

                {

                    return echostr;

                }

            }

            return "";

        }

 /// <summary>

        /// 验证微信签名

        /// </summary>

        /// * 将token、timestamp、nonce三个参数进行字典序排序

        /// * 将三个参数字符串拼接成一个字符串进行sha1加密

        /// * 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。

        /// <returns></returns>

        private bool CheckSignature(string signature, string timestamp, string nonce)

        {

            string[] ArrTmp = { Token, timestamp, nonce };

            Array.Sort(ArrTmp); //字典排序

            string tmpStr = string.Join("", ArrTmp);

            tmpStr = GetSHA1(tmpStr);

            tmpStr = tmpStr.ToLower();

            if (tmpStr == signature)

            {

                return true;

            }

            else

            {

                return false;

            }

        }