private void SelectAlreadySelectedPhotos()
{
if (!AllSelectedPhotos.ContainsKey(Page) || AllSelectedPhotos[Page].Count <= 0) return;
List<Photo> photos = Photos.Where(photo => AllSelectedPhotos[Page].ContainsKey(photo.Id)).ToList();
foreach (Photo photo in photos)
{
((ListBoxItem) PagePhotoList.ItemContainerGenerator.ContainerFromItem(photo)).IsSelected = true;
}
}