private void SubscribeToStateChanging(bool subscribe = true)
{
if (VisualTreeHelper.GetChildrenCount((DependencyObject)this._listScrollViewer) <= 0)
{
return;
}
FrameworkElement child = VisualTreeHelper.GetChild((DependencyObject)this._listScrollViewer, 0) as FrameworkElement;
if (child == null)
{
return;
}
VisualStateGroup visualState = MyVirtualizingPanel.FindVisualState(child, "ScrollStates");
if (visualState == null)
{
return;
}
if (subscribe)
{
visualState.CurrentStateChanging += (new EventHandler <VisualStateChangedEventArgs>(this.group_CurrentStateChanging));
}
else
{
visualState.CurrentStateChanging -= (new EventHandler <VisualStateChangedEventArgs>(this.group_CurrentStateChanging));
}
}
private static void OnItemsSourcePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
MyVirtualizingPanel virtualizingPanel = d as MyVirtualizingPanel;
if (virtualizingPanel == null)
{
return;
}
virtualizingPanel.ClearItems();
INotifyCollectionChanged collection1 = e.OldValue as INotifyCollectionChanged;
if (collection1 != null)
{
virtualizingPanel.UnhookCollectionChanged(collection1);
}
INotifyCollectionChanged collection2 = e.NewValue as INotifyCollectionChanged;
if (collection2 == null)
{
return;
}
List <IVirtualizable> virtualizableList = new List <IVirtualizable>();
foreach (object obj in (IEnumerable)(collection2 as ICollection))
{
if (obj is IVirtualizable)
{
virtualizableList.Add(obj as IVirtualizable);
}
}
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)virtualizableList);
virtualizingPanel.HookUpCollectionChanged(collection2);
}
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 static void OnItemsSourcePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
MyVirtualizingPanel virtualizingPanel = d as MyVirtualizingPanel;
if (virtualizingPanel == null)
{
return;
}
virtualizingPanel.ClearItems();
// ISSUE: explicit reference operation
INotifyCollectionChanged oldValue = e.OldValue as INotifyCollectionChanged;
if (oldValue != null)
{
virtualizingPanel.UnhookCollectionChanged(oldValue);
}
// ISSUE: explicit reference operation
INotifyCollectionChanged newValue = e.NewValue as INotifyCollectionChanged;
if (newValue == null)
{
return;
}
List <IVirtualizable> virtualizableList = new List <IVirtualizable>();
IEnumerator enumerator = (newValue as ICollection).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();
}
}
virtualizingPanel.AddItems((IEnumerable <IVirtualizable>)virtualizableList);
virtualizingPanel.HookUpCollectionChanged(newValue);
}
private void HookupScrollEvents()
{
if (this.ScrollViewer == null)
{
return;
}
FrameworkElement child = VisualTreeHelper.GetChild((DependencyObject)this.ScrollViewer, 0) as FrameworkElement;
if (child == null)
{
return;
}
VisualStateGroup visualState = MyVirtualizingPanel.FindVisualState(child, "VerticalCompression");
if (visualState == null)
{
return;
}
visualState.CurrentStateChanging += (new EventHandler <VisualStateChangedEventArgs>(this.vgroup_CurrentStateChanging));
}
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]);
}
}
