/// <summary>

        /// 将参数扩展为指定长度的字符串，不足位数的在前方加0

        /// </summary>

        /// <param name="origin"></param>

        /// <param name="length"></param>

        /// <returns></returns>

        public static string GetLengthString(string origin, int length)

        {

            int l = origin.Length;

            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < length - l; i++)

                sb.Append("0");

            sb.Append(origin);

            return sb.ToString();

        }