很简单:只需处理WM_SYSCOMMAND消息:
procedure TfrmMain.WndProc(var Message: TMessage);
begin
case Message.Msg of
WM_SYSCOMMAND:
case Message.WParam of
SC_MINIMIZE:
inherited;
Hide;//隐藏主程序
SetWindowLong(Application.Handle, GWL_EXSTYLE, WS_EX_TOOLWINDOW);//隐藏任务栏上的程序图标
...
end;
...
end;
end;