签名：实现参数字典排序，然后拼接为url参数形式

在很多地方请求参数需要做处理例如：

步骤

1.参数字典排序。

2.拼接字符。

        /// <summary>
        /// 生成签名
        /// </summary>
        /// <param name="paramlst">参数列表</param>
        /// <param name="IsToUpper">是否转大写</param>
        /// <param name="IsDirect">是否直接加上签名Key</param>
        /// <returns></returns>
        public static string GenerateSign(List<KeyValuePair<string, string>> lst,string privateKey)
        {
            Comparison<KeyValuePair<string, string>> Comparer = new Comparison<KeyValuePair<string, string>>(CompareKeyValuepair);
            lst.Sort(Comparer);
            var paramlst =  lst.Where(p => !string.IsNullOrEmpty(p.Value)).ToList();
            string signstr = string.Join("&", paramlst.Select(p => p.Key + "=" + p.Value)) + privateKey;
            return Sign(signstr, "UTF-8");
        }

        /// <summary>
        /// 根据Key比较排序位置
        /// </summary>
        private static int CompareKeyValuepair(KeyValuePair<string, string> p1, KeyValuePair<string, string> p2)
        {
            return string.Compare(p1.Key, p2.Key);
        }        

3.MD5加密

/// <summary>
        /// 签名字符串
        /// </summary>
        /// <param name="prestr">需要签名的字符串</param>
        /// <param name="key">密钥</param>
        /// <param name="inputCharset">编码格式</param>
        /// <returns>签名结果</returns>
        public static string Sign(string prestr, string inputCharset)
        {
            StringBuilder sb = new StringBuilder();
            MD5 md5 = new MD5CryptoServiceProvider();
            byte[] t = md5.ComputeHash(Encoding.GetEncoding(inputCharset).GetBytes(prestr));
            foreach (byte t1 in t)
            {
                sb.Append(t1.ToString("x2"));
            }
            return sb.ToString();
        }

第二套加密、排序方法

        public static bool IdentifySign<T>(T entity, string keys = "aiHpJWIlmXhb7JrwOCon", string charSet = "utf-8")
           where T : new()
        {
            if (entity == null)
            {
                entity = new T();
            }
            StringBuilder sb = new StringBuilder();
            Type type = typeof(T);
            PropertyInfo[] pi = type.GetProperties();
            var tt = pi.OrderBy(t => t.Name);
            string sign = "";
            foreach (var item in tt)
            {
                //参数为空不参与MD5计算
                if (item.GetValue(entity, null) == null) continue;
                if (item.Name == "sign")
                {
                    sign = item.GetValue(entity, null).ToString();
                    continue;
                }
                if (item.GetValue(entity, null) is ICollection)
                {
                    sb.Append(item.Name + "=" +
                              Newtonsoft.Json.JsonConvert.SerializeObject(item.GetValue(entity, null)) + "&");
                    continue;
                }

                sb.Append(item.Name + "=" + item.GetValue(entity, null) + "&");
            }
            string signStr = sb.ToString().TrimEnd('&') + "&key=" + keys;
            var urlmd5 = DESEncrypt.MD5ToUpper(signStr, charSet);

            return urlmd5 == sign;

        }

        public static string LuckDrawPostSign<T>(T entity, string keys = "aiHpJWIlmXhb7JrwOCon",
            string charSet = "gb2312") where T : new()
        {
            if (entity == null)
            {
                entity = new T();
            }
            StringBuilder sb = new StringBuilder();
            Type type = typeof(T);
            PropertyInfo[] pi = type.GetProperties();
            var tt = pi.OrderBy(t => t.Name);
            var jo = new JObject();
            foreach (var item in tt)
            {
                //参数为空不参与MD5计算
                if (item.GetValue(entity, null) == null) continue;
                sb.Append(item.Name + "=" + item.GetValue(entity, null) + "&");
                jo.Add(item.Name, item.GetValue(entity, null).ToString());
            }

            var urlmd5 = DESEncrypt.MD5ToUpper(sb.ToString() + "key=" + keys, charSet);
            jo.Add("sign", urlmd5);
            return jo.ToString();
        }