Problem mit Hinzufügen von neuem Song

[DelphiUser7]

Hi,
wie kann ich machen, dass der TMediaPlayer weiterspielt, wenn ich einer PlayList (TListBox) eine neue Datei hinzufüge?;
mein Play-Button:

Delphi-Quellcode:

procedure TForm1.BitBtn1Click(Sender: TObject);
var a: integer;
begin
  If PlayL1.Items.Count = 0 then begin
      Mediaplayer1.FileName := FileLoad1.FileName;
    end else begin
      Mediaplayer1.FileName := PlayL1.Items.Strings[PlayL1.ItemIndex];
   end;
   if Mediaplayer1.Mode = mpPlaying then begin
    Mediaplayer1.FileName := PlayL1.Items.Strings[PlayL1.ItemIndex];
    Stunden := 0; Minuten := 0; Sekunden := 0;
    TimePanelMain.Caption := '00:00:00';
    Mediaplayer1.StartPos := 0;
    mediaplayer1.Play;
   end;
    myLabel.Enabled := true;
    myLabel.Caption := Mediaplayer1.FileName;
    mediaplayer1.Open;
    Mediaplayer1.Play;
    Timer1.Enabled := True;
   if Mediaplayer1.Position = mediaplayer1.EndPos then begin
    //a := PlayL1.ItemIndex;
    //a := a+1;
    //mediaplayer1.Play; //...Bau;
   end;

So füge ich Dateien hinzu:

Delphi-Quellcode:

procedure TForm1.FileChoseClick(Sender: TObject);
begin
 with FileLoad2 do begin
  FileLoad2.Filter := 'mp3-Files(*.mp3)|*.mp3|wav-Files(*.wav)|*.wav|midi-Files(*.mid)|*.mid';
   end;
  if FileLoad2.Execute then begin
   try
    if Mediaplayer1.Mode = mpOpen then begin
    newplaylist.Add(IntToStr(tracknr)+#9+extractFileName(fileLoad1.fileName));
    PlayL1.Items.Assign(newplaylist); end;
   except
    Exit;
   end;
 end;
end;

Gruss
DelphiUser7