public void SetMode(AppMode newMode)
        {
            adminPageControls.Visibility = newMode == AppMode.Admin ? Visibility.Visible : Visibility.Collapsed;
            adminTechNextPage.Visibility = pageCount > 1 && newMode != AppMode.Slide ? Visibility.Visible : Visibility.Collapsed;

            if (newMode == AppMode.Slide && pageCount > 1)
            {
                SlideIntervalValueChanged(this, null);
            }
            else
            {
                AppTimer.Unsubscribe(this);
            }

            if (newMode == AppMode.Slide)
            {
                Save();
            }
        }
 private void SlideIntervalValueChanged(object sender, RoutedPropertyChangedEventArgs <object> e)
 {
     AppTimer.Unsubscribe(this);
     AppTimer.Subscribe(this, TimerInterval.Seconds, (int)slideInterval.Value);
 }