自动编号也疯狂

'===============================================================================
'-函数名称:         autoID
'-功能描述:         自动编号 ,
'-输入参数说明:     参数1:tblname 表名
'                   参数2:fldname 字段名
'                   参数3:intlength增长号的长度
'                   参数4:prefix 前缀(可选参数)
'                   参数5:dateformat时间前缀(可选参数)
'-返回参数说明:     可以按时间自增长编号, 如果没有时间就自增长编号
'-使用语法示例:     AutoID("型体编号表", "型体编号", 4, "GL")
'                   AutoID("型体编号表", "型体编号", 4)
'                   AutoID("型体编号表", "型体编号", 4, "GL","yyyymmdd")
'-参考:
'-使用注意:
'-兼容性:           2000,XP,2003
'-作者:             Victor Duane
'-更新日期：        2007-12-5 17:03
'===============================================================================
Function AutoID(tblName As String, fldName As String, intLength As Integer, Optional Prefix As String = "", Optional DateFormat As String = "") As String
'自动编号 , 可以按时间自增长编号, 如果没有时间就自增长编号
Dim rs As New ADODB.Recordset
Dim cn As New ADODB.Connection

Dim intDate As Integer
Dim intPrefix As Integer

Dim strDate As String
Dim strToday As String
Dim OldDate As String

'如果DateFormat为空,当天日期为空,否则为当天日期
If Len(DateFormat) = 0 Then
    strToday = ""
Else
    strToday = Format(Date, DateFormat)
End If

strDate = strToday
intDate = Len(strDate) '取得时间的长度
intPrefix = Len(Prefix) '取得前缀的长度

Set cn = CurrentProject.Connection
Dim strSQL As String
strSQL = "select * from " & tblName & " order by " & fldName
rs.Open tblName, cn, 1, 2

Debug.Print rs.RecordCount
If rs.RecordCount > 0 Then
    rs.MoveLast
    '取得最大值的时间前缀
    OldDate = Nz(Mid$(rs(fldName), intPrefix + 1, intDate), "")
    '判断新增的值是否跨时间
    If strToday = OldDate Then
        AutoID = Prefix & strDate & Format(Val(Right$(rs(fldName), intLength) + 1), String(intLength, "0"))
    Else
        AutoID = Prefix & strDate & String(intLength - 1, "0") & "1"
    End If
Else
    AutoID = Prefix & strDate & String(intLength - 1, "0") & "1"
End If

rs.Close
cn.Close
Set rs = Nothing
Set cn = Nothing
End Function