How can I sanitize a string for use as a filename?

Question

I\'ve got a routine that converts a file into a different format and saves it. The original datafiles were numbered, but my routine gives the output a filename based on an

Answer 1

// for all platforms (Windows\Unix), uses IOUtils.
function ReplaceInvalidFileNameChars(const aFileName: string; const aReplaceWith: Char = '_'): string;
var
  i: integer;
begin
  Result := aFileName;
  for i := Low(Result) to High(Result) do
    if not TPath.IsValidFileNameChar(Result[i]) then
      Result[i] := aReplaceWith;
  end;
end.