private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var excludedItems = Filter?.ExcludedItems ?? new string[0];

            var selectedItems   = _listBox.SelectedItems.Cast <string>().ToArray();
            var unselectedItems = _listBox.Items.Cast <string>().Except(selectedItems).ToArray();

            excludedItems = excludedItems.Except(selectedItems).Concat(unselectedItems).Distinct().ToArray();

            Filter = new MultipleChoiceContentFilter(excludedItems);
        }
 private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     Filter = new MultipleChoiceContentFilter(_listBox?.SelectedItems.Cast <string>());
 }
 private void ListBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
 {
     Filter = new MultipleChoiceContentFilter(_listBox?.SelectedItems.Cast<string>());
 }