高手请教！阿拉伯数字自动转换成中文大写的问题？急！

'主函数
'调用方法
'Response.Write ConvertSum(CStr(123.50))
Function ConvertSum(str)
  if IsPositveDecimal(str)=False Then
     ConvertSum="输入的不是正数字！"
  Else  
     if CDbl(str)>999999999999.99 Then
        ConvertSum="数字太大，无法换算，请输入一万亿元以下的金额"
     else  
        Dim splitstr '定义按小数点分割后的字符串数组
        splitstr=Split(str,".")'按小数点分割字符串   
        if UBound(splitstr)=0 Then'只有整数部分
            ConvertSum=ConvertData(str)&"圆整"
        else '有小数部分
            Dim rstr
            rstr=ConvertData(splitstr(0))&"圆"'转换整数部分
            rstr=rstr&ConvertXiaoShu(splitstr(1))'转换小数部分
            ConvertSum=rstr
        End IF
     End IF
  End IF  
End Function

'判断是否是正数字字符串
'判断字符串
'如果是数字，返回true，否则返回false
Function IsPositveDecimal(str)
  On Error Resume Next
  IF VarType(CInt(str))<>2 Then
     IsPositveDecimal=False
  Else
     IsPositveDecimal=True
  End IF
End Function

'转换数字（整数）
'需要转换的整数数字字符串
'转换成中文大写后的字符串
Function ConvertData(str)
  Dim tmpstr
  Dim rstr
  Dim strlen
  strlen=Len(str)
  if strlen<=4 Then'数字长度小于四位
     rstr=ConvertDigit(str)
  else
     if strlen<=8 Then '数字长度大于四位，小于八位
        tmpstr=Mid(str,strlen-4,4)'先截取最后四位数字
        rstr=ConvertDigit(tmpstr)'转换最后四位数字
        tmpstr=Mid(str,1,strlen-4)'截取其余数字
        '将两次转换的数字加上萬后相连接
        rstr=ConvertDigit(tmpstr)&"萬"&rstr
        rstr=Replace(rstr,"零萬","萬")
        rstr=Replace(rstr,"零零","零")
    else
        if strlen<=12 Then'数字长度大于八位，小于十二位
           tmpstr=Mid(str,strlen-4,4)'先截取最后四位数字
           rstr=ConvertDigit(tmpstr)'转换最后四位数字
           tmpstr=Mid(str,strlen-8,4)'再截取四位数字
           rstr=ConvertDigit(tmpstr)&"萬"&rstr
           tmpstr=Mid(str,1,strlen-8)
           rstr=ConvertDigit(tmpstr)&"億"&rstr
           rstr=Replace(rstr,"零億","億")
           rstr=Replace(rstr,"零萬","零")
           rstr=Replace(rstr,"零零","零")
           rstr=Replace(rstr,"零零","零")
       End IF
   End IF
End IF
strlen=Len(rstr)
if strlen>=2 Then
    select case Mid(rstr,strlen-2,2)
        case "佰零"
           rstr=Mid(rstr,1,strlen-2)&"佰"
        case "仟零"
           rstr=Mid(rstr,1,strlen-2)&"仟"
        case "萬零"
           rstr=Mid(rstr,1,strlen-2)&"萬"
        case "億零"
           rstr=Mid(rstr,1,strlen-2)&"億"
     End select
  End IF
  ConvertData=rstr
End Function
'转换数字（小数部分）
'需要转换的小数部分数字字符串
'转换成中文大写后的字符串
Function ConvertXiaoShu(str)
  Dim strlen
  strlen=Len(str)
  Dim rstr
  if strlen=1 Then
      rstr=ConvertChinese(str)&"角"
      ConvertXiaoShu=rstr
  else
     Dim tmpstr
     tmpstr=Mid(str,1,1)
     rstr=ConvertChinese(tmpstr)&"角"
     tmpstr=Mid(str,2,1)
     rstr=rstr&ConvertChinese(tmpstr)&"分"
     rstr=Replace(rstr,"零分","")
     rstr=Replace(rstr,"零角","")
     ConvertXiaoShu=rstr
  End If
End Function

'转换数字
'转换的字符串（四位以内）  
Function ConvertDigit(str)
  Dim strlen
  strlen=Len(str)
  Dim rstr
  select case strlen  
      case 1
        rstr=ConvertChinese(str)
      case 2
        rstr=Convert2Digit(str)
      case 3
        rstr=Convert3Digit(str)
      case 4
        rstr=Convert4Digit(str)
    end select
    rstr=Replace(rstr,"拾零","拾")
    strlen=Len(rstr)
    ConvertDigit=rstr
End Function

'转换四位数字  
Function Convert4Digit(str)
  Dim str1,str2,str3,str4
  str1=Mid(str,1,1)
  str2=Mid(str,2,1)
  str3=Mid(str,3,1)
  str4=Mid(str,4,1)
  Dim rstring
  rstring=rstring&ConvertChinese(str1)&"仟"
  rstring=rstring&ConvertChinese(str2)&"佰"
  rstring=rstring&ConvertChinese(str3)&"拾"
  rstring=rstring&ConvertChinese(str4)
  rstring=Replace(rstring,"零仟","零")
  rstring=Replace(rstring,"零佰","零")
  rstring=Replace(rstring,"零拾","零")
  rstring=Replace(rstring,"零零","零")
  rstring=Replace(rstring,"零零","零")
  rstring=Replace(rstring,"零零","零")
  Convert4Digit=rstring
End Function

'转换三位数字
Function Convert3Digit(str)
  Dim str1,str2,str3
  str1=Mid(str,1,1)
  str2=Mid(str,2,1)
  str3=Mid(str,3,1)
  Dim rstring
  rstring=rstring&ConvertChinese(str1)&"佰"
  rstring=rstring&ConvertChinese(str2)&"拾"
  rstring=rstring&ConvertChinese(str3)
  rstring=Replace(rstring,"零佰","零")
  rstring=Replace(rstring,"零拾","零")
  rstring=Replace(rstring,"零零","零")
  rstring=Replace(rstring,"零零","零")
Convert3Digit=rstring
End Function

'转换二位数字
Function Convert2Digit(str)
  Dim str1,str2
  str1=Mid(str,1,1)
  str2=Mid(str,2,1)
  Dim rstring
  rstring=rstring&ConvertChinese(str1)&"拾"
  rstring=rstring&ConvertChinese(str2)
  rstring=Replace(rstring,"零拾","零")
  rstring=Replace(rstring,"零零","零")
  Convert2Digit=rstring
End Function

'将一位数字转换成中文大写数字
Function ConvertChinese(str)
  '"零壹贰叁肆伍陆柒捌玖拾佰仟萬億圆整角分"
  Dim cstr
  select case(str)
     case "0"
        cstr="零"
     case "1"
        cstr="壹"
     case "2"
        cstr="贰"
     case "3"
        cstr="叁"
     case "4"
        cstr="肆"
     case "5"
        cstr="伍"
     case "6"
        cstr="陆"
     case "7"
        cstr="柒"
     case "8"
        cstr="捌"
     case "9"
        cstr="玖"
   end select
  ConvertChinese=cstr
End Function