void IListenCollectionChanged.CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
for (int i = 0; i < e.NewItems.Count; i++)
{
Items.InsertImpl(e.NewStartingIndex + i, e.NewItems[i]);
}
break;
case NotifyCollectionChangedAction.Remove:
for (int i = 0; i < e.OldItems.Count; i++)
{
Items.RemoveAtImpl(e.OldStartingIndex);
}
break;
case NotifyCollectionChangedAction.Replace:
for (int i = 0; i < e.NewItems.Count; i++)
{
Items.SetItemImpl(e.NewStartingIndex + i, e.NewItems[i]);
}
break;
case NotifyCollectionChangedAction.Reset:
Items.ClearImpl();
foreach (var v in ItemsSource)
{
Items.AddImpl(v);
}
break;
}
OnItemsChanged(e);
}
internal virtual void OnItemsSourceChanged(IEnumerable oldSource, IEnumerable newSource)
{
if (CollectionListener != null)
{
CollectionListener.Detach();
CollectionListener = null;
}
if (newSource != null)
{
if (newSource is INotifyCollectionChanged)
{
CollectionListener = new WeakCollectionChangedListener(((INotifyCollectionChanged)newSource), this);
}
Items.SetIsReadOnly(true);
itemsIsDataBound = true;
Items.ClearImpl();
foreach (var v in newSource)
{
Items.AddImpl(v);
}
// Setting itemsIsDataBound to true prevents normal notifications from propagating, so do it manually here
OnItemsChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
else
{
itemsIsDataBound = false;
Items.SetIsReadOnly(false);
Items.ClearImpl();
}
// Yes this is stupid and shouldn't be here, but DRT 348 sets an empty collection as the ItemsSource
// and expects the LayoutUpdated event to be raised. This is the only way that makes sense for this
// to happen. It's all very strange.
InvalidateMeasure();
}