public new void Clear()
 {
     CollectionChangeNotice?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
     base.Clear();
 }
 public new void Remove(ListItem item)
 {
     CollectionChangeNotice?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item));
     base.Remove(item);
 }
 public new void Add(ListItem item)
 {
     CollectionChangeNotice?.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item));
     base.Add(item);
 }