/// <summary>

        /// c# 参数名ascii码从小到大排序(字典序)拼接

        /// </summary>

        /// <param name="dir"></param>

        /// <returns></returns>

        public static string AsciiDicToStr(Dictionary<string, string> dir)

        {

            string[] arrKeys = dir.Keys.ToArray();

            Array.Sort(arrKeys, string.CompareOrdinal);

            var sb = new StringBuilder();

            foreach (var key in arrKeys)

            {

                string value = dir[key];

                sb.Append(key + "=" + value + "&");

            }

            return sb.ToString().Substring(0, sb.ToString().Length - 1);

        }