C# 多进制转换

    public class Converter
    {
        private static String keys = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";//编码,可加一些字符也可以实现72,96等任意进制转换，但是有符号数据不直观，会影响阅读。
        private static int exponent = keys.Length;//幂数

        //string conn_Str = "";

        /// <summary>
        /// 十进制转多进制
        /// </summary>
        /// <param name="value">十进制的值<</param>
        /// <param name="s">进制字符<</param>
        /// <param name="k">多少进制<</param>
        /// <returns>Return a specified 62 encode string</returns>
        public static string Decimal2Str(decimal value, string s = "", int k = )
        {
            string result = string.Empty;
            if (s != "")
            {
                keys = s;
            }
            else
            {
                if (k >=  && k <= )//二进制到36进制
                {
                    keys = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
                    keys = keys.Substring(, k);
                }
            }
            exponent = keys.Length;
            do
            {
                decimal index = value % exponent;
                result = keys[(int)index] + result;
                value = (value - index) / exponent;
            }
            while (value > );

            return result;
        }

        /// <summary>
        /// 多进制转十进制
        /// </summary>
        /// <param name="value">多进制的值</param>
        /// <param name="s">进制字符<</param>
        /// <param name="k">多少进制<</param>
        /// <returns>Return a specified decimal number that decode by 62 string</returns>
        public static decimal Str2Decimal(string value, string s = "", int k = )
        {
            decimal result = ;
            if (s != "")
            {
                keys = s;
            }
            else
            {
                if (k >=  && k <= )//二进制到36进制
                {
                    keys = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
                    keys = keys.Substring(, k);
                }
            }
            exponent = keys.Length;
            for (int i = ; i < value.Length; i++)
            {
                int x = value.Length - i - ;
                result += keys.IndexOf(value[i]) * Pow(exponent, x);// Math.Pow(exponent, x);
            }
            return result;
        }

        /// <summary>
        /// 一个数据的N次方
        /// </summary>
        /// <param name="x"></param>
        /// <returns></returns>
        private static decimal Pow(decimal baseNo, decimal x)
        {
            decimal value = ;////1 will be the result for any number's power 0.任何数的0次方，结果都等于1
            while (x > )
            {
                value = value * baseNo;
                x--;
            }
            return value;
        }
    }