Zwei ListBoxen gleichzeitig scrollen?

[sniper_w]

Hier etwas Konkretes:

Delphi-Quellcode:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TMyListBox = class(TListBox)
  private
    FRef : TCustomListBox;
    procedure WMHScroll(var Message: TWMHScroll); message WM_HSCROLL;
    procedure WMVScroll(var Message: TWMVScroll); message WM_VSCROLL;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property Reference : TCustomListBox read FRef write FRef;
  end;
  TForm1 = class(TForm)
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
    LBox : TMyListBox;
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
 var a:integer;
begin
 Randomize;
  LBox := TMyListBox.Create(self);
  with LBox do
  begin
   Parent := Self;
   Visible := true;
   Top := 10;
   Left := 10;
   Width := 200;
   Height := 200;
   Reference := listbox1;
  end;

  for a:=0 to 100 do
  begin
   ListBox1.Items.Add(IntToStr(Random(100000)));
   LBox.Items.Add(IntToStr(Random(100000)));
  end;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
 LBox.Free;
end;

{ TMyListBox }

constructor TMyListBox.Create(AOwner: TComponent);
begin
  inherited;
  FRef := nil;
end;

procedure TMyListBox.WMHScroll(var Message: TWMHScroll);
begin
 inherited;
end;

procedure TMyListBox.WMVScroll(var Message: TWMVScroll);
begin
 inherited;
 if Assigned(FRef) then FRef.TopIndex := TopIndex;
end;