private void dispatcherTimer_Tick(object sender, EventArgs e)
        {
            if (currentAnnouncement < announcementsCount)
            {
                LoadContent();
                currentAnnouncement++;
            }
            else
            {
                LoadAnnouncements();
                announcementsCount  = announcements.Count;
                currentAnnouncement = 0;
            }

            LoadNews();
            Vijesti = new FITNewsViewModel(lista);
        }
        public MainWindowViewModel()
        {
            LoadNews();
            LoadAnnouncements();
            announcementsCount = announcements.Count;

            if (announcementsCount > 0)
            {
                LoadContent();
                currentAnnouncement++;
            }

            Vijesti = new FITNewsViewModel(lista);

            DispatcherTimer dispatcherTimer = new DispatcherTimer();

            dispatcherTimer.Tick    += new EventHandler(dispatcherTimer_Tick);
            dispatcherTimer.Interval = new TimeSpan(0, 0, 10);
            dispatcherTimer.Start();
        }