Question

Is there something like this, that only leaves numbers, letters and underscore for spaces?

Server.URLEncode isn’t quite what i’m looking for.

Answer 1

There is no an integrated function as you described in ASP.
But you can do with regular expressions.
May be as follows:

Function FileNameEncode(ByVal strFileName)
    Dim oReg
    Set oReg = New RegExp
    oReg.IgnoreCase = True
    oReg.Global = True
    oReg.Pattern = "[^a-z\d\s.]+"
    FileNameEncode = Replace(oreg.Replace(strFileName, ""), " ", "_")
    Set oReg = Nothing
End Function

'FileNameEncode("letters é$- 123ÖÇ.bat") returns "letters__123.bat"

If you pass filename without extension as parameter, you could remove the dot char from pattern.