C# 數字轉換大寫金額

        string[] bitStr ={ "零", "壹", "貳", "叄", "肆", "伍", "陸", "柒", "捌", "玖" };//定義個位數字
        string[] medianStr ={ "", "拾", "佰", "仟" };
        string[] pointStr ={ "角", "分" };
        /// <summary>
        /// 在萬億以類的數字
        /// </summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public string GetCNMoney(decimal value)
        {

            if (value > 999999999999)
            {
                return value.ToString("f2");
            }
            string strValue = value.ToString("f2"); //因爲這一塊用的是f2,保留兩位小數,肯定會有小數點,所以下面先不進行判斷
           
            //得到整數跟小數部分

            string integralValue = strValue;
            string pointValue = string.Empty;
            if (strValue.IndexOf('.') > 0)
            {
                integralValue = strValue.Substring(0, strValue.IndexOf('.'));
                pointValue = strValue.Substring(strValue.IndexOf('.')+1);

            }

            StringBuilder  sb=new StringBuilder();

            if (integralValue.Length > 8) //上億的數
            {
                string tempValue = integralValue.Substring(0, integralValue.Length - 8); //得到億以上部分
                sb.Append(GetCNNumber(tempValue));
                sb.Append("億");

                sb.Append(GetCNNumber(integralValue.Substring(integralValue.Length - 8,4)));
                sb.Append("萬");
                sb.Append(GetCNNumber(integralValue.Substring(integralValue.Length - 4)));

            }
            else if (integralValue.Length > 4)
            {
                string tempValue =integralValue.Substring(0,integralValue.Length - 4); //得到萬以上部分
                sb.Append(GetCNNumber(tempValue));
                sb.Append("萬");
                sb.Append(GetCNNumber(integralValue.Substring(integralValue.Length - 4)));
            }
            else
            {
                sb.Append(GetCNNumber(integralValue));
            }
            sb.Append("圓");
            sb.Append(GetCNPoint(pointValue));
            return sb.ToString();
        }

        /// <summary>
        /// 得到一萬以內的數的大寫形式
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        private string GetCNNumber(string str)
        {
            //string ret = string.Empty;
            StringBuilder sb = new StringBuilder();
            int len = str.Length;
            //得到1-10000以內的數
            for (int i = 0; i < str.Length; i++)
            {
                int temp = int.Parse(str.Substring(i, 1));
                sb.Append(bitStr[temp]);
                sb.Append(medianStr[len - 1 - i]);
            }
            return sb.ToString();
        }

        /// <summary>
        /// 得到角,分
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public string GetCNPoint(string str)
        {
            StringBuilder sb = new StringBuilder();
            for(int i=0;i<str.Length;i++)
            {
                int temp = int.Parse(str.Substring(i, 1));
                sb.Append(bitStr[temp]);
                sb.Append(pointStr[pointStr.Length - 1 - i]);
            }
            return sb.ToString();
        }