(Delphi) ListFileDir

procedure ListFileDir(Path: string; FileList: TStrings);
var
  SR: TSearchRec;
begin
  if FindFirst(Path + '*.*', faAnyFile, SR) = 0 then
  begin
    repeat
      if (SR.Attr <> faDirectory) then
      begin
        FileList.Add(SR.Name);
      end;
    until FindNext(SR) <> 0;
    FindClose(SR);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  ListFileDir('C:\WINDOWS\', ListBox1.Items);
end;