private void onUpButtonTapped(object sender, TappedRoutedEventArgs e)
        {
            if (_folderTree.Count > 0)
            {
                _currentFolder = _folderTree.Last<DataStructure.Folder>();

                folder.Source = _currentFolder.folderInnerFolders;
                file.Source = _currentFolder.folderFiles;

                _folderTree.RemoveAt(_folderTree.Count - 1);
            }
            else
            {
                _currentFolder = null;

                folder.Source = _currentWorkbin.workbinFolders;
                file.Source = new List<DataStructure.File>();
                upFolderButton.Visibility = Visibility.Collapsed;
                upFolderButton_snapped.Visibility = Visibility.Collapsed;
            }
        }
        private void onFolderSelected(object sender, TappedRoutedEventArgs e)
        {
            if (_currentFolder != null)
            {
                _folderTree.Add(_currentFolder);
            }

            _currentFolder = (e.OriginalSource as FrameworkElement).DataContext as DataStructure.Folder;

            this.folder.Source = _currentFolder.folderInnerFolders;
            this.file.Source = _currentFolder.folderFiles;

            upFolderButton.Visibility = Visibility.Visible;
            upFolderButton_snapped.Visibility = Visibility.Visible;
        }