private void collection_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
MyVirtualizingPanel virtualizingPanel = this;
List <IVirtualizable> itemsToInsert = new List <IVirtualizable>();
if (e.NewItems != null)
{
foreach (object newItem in (IEnumerable)e.NewItems)
{
if (newItem is IVirtualizable)
{
itemsToInsert.Add(newItem as IVirtualizable);
}
}
}
List <IVirtualizable> virtualizableList = new List <IVirtualizable>();
if (e.OldItems != null)
{
foreach (object oldItem in (IEnumerable)e.OldItems)
{
if (oldItem is IVirtualizable)
{
virtualizableList.Add(oldItem as IVirtualizable);
}
}
}
if (e.Action == NotifyCollectionChangedAction.Add)
{
if (e.NewStartingIndex >= virtualizingPanel.VirtualizableItems.Count)
{
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)itemsToInsert);
}
else
{
virtualizingPanel.InsertRemoveItems(e.NewStartingIndex, itemsToInsert, virtualizingPanel.KeepScrollPositionWhenAddingItems, (IVirtualizable)null);
}
}
else if (e.Action == NotifyCollectionChangedAction.Reset)
{
virtualizingPanel.ClearItems();
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)virtualizingPanel.ItemsSource);
}
else
{
if (e.Action != NotifyCollectionChangedAction.Remove || virtualizableList.Count <= 0)
{
return;
}
virtualizingPanel.RemoveItem(virtualizableList[0]);
}
}
private void collection_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
MyVirtualizingPanel virtualizingPanel = this;
List <IVirtualizable> itemsToInsert = new List <IVirtualizable>();
if (e.NewItems != null)
{
IEnumerator enumerator = e.NewItems.GetEnumerator();
try
{
while (enumerator.MoveNext())
{
object current = enumerator.Current;
if (current is IVirtualizable)
{
itemsToInsert.Add(current as IVirtualizable);
}
}
}
finally
{
IDisposable disposable = enumerator as IDisposable;
if (disposable != null)
{
disposable.Dispose();
}
}
}
List <IVirtualizable> virtualizableList = new List <IVirtualizable>();
if (e.OldItems != null)
{
IEnumerator enumerator = e.OldItems.GetEnumerator();
try
{
while (enumerator.MoveNext())
{
object current = enumerator.Current;
if (current is IVirtualizable)
{
virtualizableList.Add(current as IVirtualizable);
}
}
}
finally
{
IDisposable disposable = enumerator as IDisposable;
if (disposable != null)
{
disposable.Dispose();
}
}
}
if (e.Action == NotifyCollectionChangedAction.Add)
{
if (e.NewStartingIndex >= virtualizingPanel.VirtualizableItems.Count)
{
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)itemsToInsert);
}
else
{
virtualizingPanel.InsertRemoveItems(e.NewStartingIndex, itemsToInsert, virtualizingPanel.KeepScrollPositionWhenAddingItems, null);
}
}
else if (e.Action == NotifyCollectionChangedAction.Reset)
{
virtualizingPanel.ClearItems();
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)virtualizingPanel.ItemsSource);
}
else
{
if (e.Action != NotifyCollectionChangedAction.Remove || virtualizableList.Count <= 0)
{
return;
}
virtualizingPanel.RemoveItem(virtualizableList[0]);
}
}
