private void FilterItems()
{
IEnumerable source = ItemsSource;
if (source == null)
{
FilteredItems.Clear();
return;
}
IEnumerator enumerator = source.GetEnumerator();
if (!enumerator.MoveNext())
{
FilteredItems.Clear();
return;
}
FilterPredicate predicate = Predicate;
FilteredCollection filtered = new FilteredCollection();
do
{
object item = enumerator.Current;
if (predicate == null || predicate.Matches(item))
{
filtered.Add(item);
}
}while (enumerator.MoveNext());
FilteredItems = filtered;
}
private void RegisterPredicate(FilterPredicate predicate)
{
if (predicate != null)
{
predicate.ItemsSource = ItemsSource;
predicate.FilterRequired += OnFilterRequired;
}
}
private void UnregisterPredicate(FilterPredicate predicate)
{
if (predicate != null)
{
predicate.FilterRequired -= OnFilterRequired;
predicate.ItemsSource = null;
}
}
private static void OnItemsSourceChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
CollectionFilterBehavior behavior = (CollectionFilterBehavior)d;
FilterPredicate predicate = behavior.Predicate;
if (predicate != null)
{
predicate.ItemsSource = (IEnumerable)e.NewValue;
}
behavior.FilterItems();
}
private static void OnPredicateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
CollectionFilterBehavior behavior = (CollectionFilterBehavior)d;
FilterPredicate oldPredicate = (FilterPredicate)e.OldValue;
behavior.UnregisterPredicate(oldPredicate);
FilterPredicate newPredicate = (FilterPredicate)e.NewValue;
behavior.RegisterPredicate(newPredicate);
behavior.FilterItems();
}
