纯粹字符串操作实现

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

            Console.Write("输入任意数字，回车转换");
            Console.Write("\r\n");
            Console.Write("直接回车则退出");
            Console.Write("\r\n");

            for (; ; )
            {
                string tmpString = Console.ReadLine();

                if (tmpString.Trim() == string.Empty)
                {
                    break;
                }
                try
                {
                    Console.Write(string.Format("{0} \r\n", ConvertNumberToChineseNumber(tmpString)));
                }
                catch (Exception ex)
                {
                    Console.Write(ex.Message);
                }
            }

        }


        /// <summary>
        /// 数字转大写金额
        /// </summary>
        /// <param name="targetString">数字</param>
        /// <returns>大写金额</returns>
        private static string ConvertNumberToChineseNumber(string targetString)
        {
            string rtnValue = string.Empty;

            double tmpValue = 0;

            if (double.TryParse(targetString, out tmpValue))
            {
                rtnValue = tmpValue.ToString("#千兆#百兆#拾兆#兆#仟亿#百亿#拾亿#亿#千万#百万#拾万#万#仟#佰#拾#元.#角#分");
            }
            else
            {
                throw new Exception("输入的不是数字或者过超出范围！");
            }

            //去个头
            int firstNumberIndex = rtnValue.IndexOfAny(new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' });

            if (firstNumberIndex >= 0)
            {
                rtnValue = rtnValue.Substring(firstNumberIndex);
            }


            //去小数点或去个尾
            int lastNumberIndex = rtnValue.LastIndexOfAny(new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' });

            rtnValue = rtnValue.Substring(0, lastNumberIndex + 2);

            //小写大写切换

            rtnValue = rtnValue.Replace(".", "");
            rtnValue = rtnValue.Replace("0", "零");
            rtnValue = rtnValue.Replace("1", "壹");
            rtnValue = rtnValue.Replace("2", "贰");
            rtnValue = rtnValue.Replace("3", "叁");
            rtnValue = rtnValue.Replace("4", "肆");
            rtnValue = rtnValue.Replace("5", "伍");
            rtnValue = rtnValue.Replace("6", "陆");
            rtnValue = rtnValue.Replace("7", "柒");
            rtnValue = rtnValue.Replace("8", "捌");
            rtnValue = rtnValue.Replace("9", "玖");

            return rtnValue;
        }
    }
}