C# 数字转换成大写

/// <summary>
/// 数字转大写
/// </summary>
/// <param name="Num">数字</param>
/// <returns></returns>

public static string CmycurD(decimal num)
        {
            string str1 = "零壹贰叁肆伍陆柒捌玖";            //0-9所对应的汉字
            string str2 = "万仟佰拾亿仟佰拾万仟佰拾元角分"; //数字位所对应的汉字
            string str3 = "";    //从原num值中取出的值
            string str4 = "";    //数字的字符串形式
            string str5 = "";  //人民币大写金额形式
            int i;    //循环变量
            int j;    //num的值乘以100的字符串长度
            string ch1 = "";    //数字的汉语读法
            string ch2 = "";    //数字位的汉字读法
            int nzero = ;  //用来计算连续的零值是几个
            int temp;            //从原num值中取出的值 

            num = Math.Round(Math.Abs(num), );    //将num取绝对值并四舍五入取2位小数
            str4 = ((long)(num * )).ToString();        //将num乘100并转换成字符串形式
            j = str4.Length;      //找出最高位
            if (j > ) { return "溢出"; }
            str2 = str2.Substring( - j);   //取出对应位数的str2的值。如：200.55,j为5所以str2=佰拾元角分 

            //循环取出每一位需要转换的值
            for (i = ; i < j; i++)
            {
                str3 = str4.Substring(i, );          //取出需转换的某一位的值
                temp = Convert.ToInt32(str3);      //转换为数字
                if (i != (j - ) && i != (j - ) && i != (j - ) && i != (j - ))
                {
                    //当所取位数不为元、万、亿、万亿上的数字时
                    if (str3 == "")
                    {
                        ch1 = "";
                        ch2 = "";
                        nzero = nzero + ;
                    }
                    else
                    {
                        if (str3 != "" && nzero != )
                        {
                            ch1 = "零" + str1.Substring(temp * , );
                            ch2 = str2.Substring(i, );
                            nzero = ;
                        }
                        else
                        {
                            ch1 = str1.Substring(temp * , );
                            ch2 = str2.Substring(i, );
                            nzero = ;
                        }
                    }
                }
                else
                {
                    //该位是万亿，亿，万，元位等关键位
                    if (str3 != "" && nzero != )
                    {
                        ch1 = "零" + str1.Substring(temp * , );
                        ch2 = str2.Substring(i, );
                        nzero = ;
                    }
                    else
                    {
                        if (str3 != "" && nzero == )
                        {
                            ch1 = str1.Substring(temp * , );
                            ch2 = str2.Substring(i, );
                            nzero = ;
                        }
                        else
                        {
                            if (str3 == "" && nzero >= )
                            {
                                ch1 = "";
                                ch2 = "";
                                nzero = nzero + ;
                            }
                            else
                            {
                                if (j >= )
                                {
                                    ch1 = "";
                                    nzero = nzero + ;
                                }
                                else
                                {
                                    ch1 = "";
                                    ch2 = str2.Substring(i, );
                                    nzero = nzero + ;
                                }
                            }
                        }
                    }
                }
                if (i == (j - ) || i == (j - ))
                {
                    //如果该位是亿位或元位，则必须写上
                    ch2 = str2.Substring(i, );
                }
                str5 = str5 + ch1 + ch2;

                if (i == j -  && str3 == "")
                {
                    //最后一位（分）为0时，加上“整”
                    str5 = str5 + '整';
                }
            }
            if (num == )
            {
                str5 = "零元整";
            }
            return str5;
        }