void _galleryModel_CellClicked(GalleryModel model, GalleryCellModel cell)
 {
     if (ViewModel.IsMediaEditMode)
     {
         model.ClearSelection();
         cell.IsSelected = true;
     }
 }
        async void _galleryModel_CellDelete(GalleryModel model, GalleryCellModel cell)
        {
            if (ViewModel.IsMediaEditMode)
            {
                await MediaManager.Instance.Remove(cell.Media);

                model.RemoveCell(cell);
            }
        }