unit Unit1;
{in dcld* gepostet von Gerd Kayser}

interface

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

type
  TForm1 = class(TForm)
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
  private
    { Private-Deklarationen }
  public
    { Public-Deklarationen }
    procedure WMChangeCbChain(var Msg: TMessage); message wm_ChangeCbChain;
    procedure WMDrawClipboard(var Msg: TMessage); message wm_DrawClipboard;
  end;

var
  Form1               : TForm1;
  NextClipboardViewer : Integer;

implementation

{$R *.DFM}

procedure TForm1.WMChangeCbChain(var Msg: TMessage);
begin
  if Msg.wParam = NextClipboardViewer then
    NextClipboardViewer := Msg.lParam
  else
    SendMessage(NextClipboardViewer, wm_ChangeCbChain, Msg.wParam, Msg.lParam);
end;

procedure TForm1.WMDrawClipboard(var Msg: TMessage);
begin
  SendMessage(NextClipboardViewer, wm_DrawClipboard, Msg.wParam, Msg.lParam);
  Label1.Caption := 'Clipboard geändert um: ' + TimeToStr(Now);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  NextClipboardViewer := SetClipboardViewer(Form1.Handle);
end;

procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
  ChangeClipboardChain(Form1.Handle, NextClipboardViewer);
end;

end.