將十六進位轉八進位及八進位的方法

根據八轉十六改編 

 /// <summary>
        /// 將16進位數轉換成8進位數
        /// </summary>
        /// <param name="convertFrom">十六進位數</param>
        /// <returns>八位元</returns>
        private string ConvertNumber8To16(string convertFrom)        {
            try
            {
                string check = convertFrom.Replace("0", string.Empty).Replace("1", string.Empty).Replace("2", string.Empty).Replace("3", string.Empty).Replace("4", string.Empty).Replace("5", string.Empty).Replace("6", string.Empty).Replace("7", string.Empty).Replace("8", string.Empty).Replace("9", string.Empty).Replace("A", string.Empty).Replace("B", string.Empty).Replace("C", string.Empty).Replace("D", string.Empty).Replace("E", string.Empty).Replace("F", string.Empty);

                if (check.Length > 0)
                {
                    //errorHandle
                    return string.Empty;
                }
                string convertTo = string.Empty, convertTo2;//目標數convertTo：將八進位From轉換成進位To,

                convertTo2 = ConvertNumber16To2(convertFrom);//先轉化為二進位
                    convertTo = ConvertNumber2To8(convertTo2);
                ////把二進數轉換為十進位數
                //Int64 intTen = Convert.ToInt32(convertTo2.Trim(), 2);
                ////把十進位數轉換為八位元
                //convertTo = Convert.ToString(intTen, 8);
                return convertTo;
            }
            catch (Exception ex) { return ""; }
        }

          /// <summary>
        /// 將16進位轉換為2進位
        /// </summary>
        /// <param name="convertFrom">十六進位數</param>
        /// <returns>位元</returns>
        private string ConvertNumber16To2(string convertFrom)
        {
            string check = convertFrom.Replace("0", string.Empty).Replace("1", string.Empty).Replace("2", string.Empty).Replace("3", string.Empty).Replace("4", string.Empty).Replace("5", string.Empty).Replace("6", string.Empty).Replace("7", string.Empty).Replace("8", string.Empty).Replace("9", string.Empty).Replace("A", string.Empty).Replace("B", string.Empty).Replace("C", string.Empty).Replace("D", string.Empty).Replace("E", string.Empty).Replace("F", string.Empty);
             if (check.Length > 0)
            {
                //errorHandle
                return string.Empty;
            }
            string convertTo = string.Empty, bit;
            for (int i = convertFrom.Length - 1; i >= 0; i--)
            {
                bit = convertFrom.Substring(i, 1);
                switch (bit)
                {
                    case "0":
                        convertTo = "0000" + convertTo;
                        break;
                    case "1":
                        convertTo = "0001" + convertTo;
                        break;

                    case "2":
                        convertTo = "0010" + convertTo;
                        break;
                    case "3":
                        convertTo = "0011" + convertTo;
                        break;
                    case "4":
                        convertTo = "0100" + convertTo;
                        break;
                    case "5":
                        convertTo = "0101" + convertTo;
                        break;
                    case "6":
                        convertTo = "0110" + convertTo;
                        break;
                    case "7":
                        convertTo = "0111" + convertTo;
                        break;
                    case "8":
                        convertTo = "1000" + convertTo;
                        break;
                    case "9":
                        convertTo = "1001" + convertTo;
                        break;
                    case "A":
                        convertTo = "1010" + convertTo;
                        break;
                    case "B":
                        convertTo = "1011" + convertTo;
                        break;
                    case "C":
                        convertTo = "1100" + convertTo;
                        break;
                    case "D":
                        convertTo = "1101" + convertTo;
                        break;
                    case "E":
                        convertTo = "1110" + convertTo;
                        break;
                    case "F":
                        convertTo = "1111" + convertTo;
                        break;
                }
            }
            return convertTo;
        }

        /// <summary>
        /// 將2進位轉換為8進位
        /// </summary>
        /// <param name="convertFrom">位元</param>
        /// <returns>八位元</returns>
        private string ConvertNumber2To8(string convertFrom)
        {
            string check = convertFrom.Replace("0", string.Empty).Replace("1", string.Empty);
            if (check.Length > 0)
            {
                //errorHandle
                return string.Empty;
            }
            string convertTo = string.Empty, bit;         
            for (int i = convertFrom.Length - 3; i >= 0; i-=3)
            {
                bit = convertFrom.Substring(i, 3);//每次減3
                switch (bit)
                {
                    case "000":
                        convertTo = "0" + convertTo;
                        break;
                    case "001":
                        convertTo = "1" + convertTo;
                        break;
                    case "010":
                        convertTo = "2" + convertTo;
                        break;
                    case "011":
                        convertTo = "3" + convertTo;
                        break;
                    case "100":
                        convertTo = "4" + convertTo;
                        break;
                    case "101":
                        convertTo = "5" + convertTo;
                        break;
                    case "110":
                        convertTo = "6" + convertTo;
                        break;
                    case "111":
                        convertTo = "7" + convertTo;
                        break;            
                }
            }
            int residue, temp = 0;
            residue = convertFrom.Length % 3;//求餘數
            string s = "";
            if (residue != 0)
            {
                if (residue == 1)
                {
                   s= convertFrom.Substring(0, 1);
                   temp = 1;
                }

                if (residue == 2)
                {
                    s = convertFrom.Substring(0, 2);
                    switch (s)
                    {
                        case "01": temp = 1; break;
                        case "10": temp = 2; break;
                        case "11": temp = 3; break;

                    }
                }
            }
            if (temp != 0)
            {
                convertTo = temp.ToString() + convertTo;
            }
            return convertTo;
        }