C#將10進位轉換為16進位的方法

        /**////<summary>
        ///返回１６進位字元
        ///</summary>
        ///<param?name="value">value</param>
        ///<returns></returns>
        public static string GetHexChar(string value)
        {
            string sReturn = string.Empty;
            switch (value)
            {
                case "10":
                    sReturn = "A";
                    break;
                case "11":
                    sReturn = "B";
                    break;
                case "12":
                    sReturn = "C";
                    break;
                case "13":
                    sReturn = "D";
                    break;
                case "14":
                    sReturn = "E";
                    break;
                case "15":
                    sReturn = "F";
                    break;
                default:
                    sReturn = value;
                    break;
            }
            return sReturn;
        }

        /**////<summary>
        ///返回１６進位
        ///</summary>
        ///<param?name="value">value</param>
        ///<returns></returns>

        public static string ConvertHex(string value)
        {
            string sReturn = string.Empty;
            try
            {

                while (int.Parse(value) > 16)
                {
                    int v = int.Parse(value);
                    sReturn = GetHexChar((v % 16).ToString()) + sReturn;
                    value = Math.Floor(Convert.ToDouble(v / 16)).ToString();
                }
                sReturn = GetHexChar(value) + sReturn;
            }
            catch
            {
                sReturn = "###Valid?Value!###";
            }
            return sReturn;
        }