protected override void OnVisualChildrenChanged(DependencyObject visualAdded, DependencyObject visualRemoved)
{
// avoid reentrancy during internal updates
if (_internalUpdate)
{
return;
}
_internalUpdate = true;
try
{
// when a UIElement is added, replace it with its degenerate sibling
if (visualAdded != null)
{
Debug.Assert(!(visualAdded is DegenerateSibling),
"Unexpected addition of degenerate... All degenerates should be added during internal updates.");
UIElement element = visualAdded as UIElement;
DegenerateSibling sibling = new DegenerateSibling(element);
int index = _owner.BaseIndexOf(element);
_owner.BaseRemoveAt(index);
_owner.BaseInsert(index, sibling);
if (element != null)
{
_owner._degenerateSiblings[element] = sibling;
_owner._elements.Insert(index, element);
_owner.RaiseCollectionChanged(NotifyCollectionChangedAction.Add, element, index);
}
}
// when a degenerate sibling is removed, remove its corresponding element
if (visualRemoved != null)
{
Debug.Assert(visualRemoved is DegenerateSibling,
"Unexpected removal of UIElement... All non degenerates should be removed during internal updates.");
DegenerateSibling sibling = visualRemoved as DegenerateSibling;
int index = _owner._elements.IndexOf(sibling.Element);
_owner._elements.RemoveAt(index);
_owner.RaiseCollectionChanged(NotifyCollectionChangedAction.Remove, sibling.Element, index);
_owner._degenerateSiblings.Remove(sibling.Element);
}
}
finally
{
_internalUpdate = false;
}
}
protected override void OnVisualChildrenChanged(DependencyObject visualAdded, DependencyObject visualRemoved)
{
// avoid reentrancy during internal updates
if (_internalUpdate) return;
_internalUpdate = true;
try
{
// when a UIElement is added, replace it with its degenerate sibling
if (visualAdded != null)
{
Debug.Assert(!(visualAdded is DegenerateSibling),
"Unexpected addition of degenerate... All degenerates should be added during internal updates.");
var element = visualAdded as UIElement;
var sibling = new DegenerateSibling(element);
int index = _owner.BaseIndexOf(element);
_owner.BaseRemoveAt(index);
_owner.BaseInsert(index, sibling);
if (element != null)
{
_owner._degenerateSiblings[element] = sibling;
_owner._elements.Insert(index, element);
_owner.RaiseCollectionChanged(NotifyCollectionChangedAction.Add, element, index);
}
}
// when a degenerate sibling is removed, remove its corresponding element
if (visualRemoved != null)
{
Debug.Assert(visualRemoved is DegenerateSibling,
"Unexpected removal of UIElement... All non degenerates should be removed during internal updates.");
var sibling = (DegenerateSibling)visualRemoved;
int index = _owner._elements.IndexOf(sibling.Element);
_owner._elements.RemoveAt(index);
_owner.RaiseCollectionChanged(NotifyCollectionChangedAction.Remove, sibling.Element, index);
_owner._degenerateSiblings.Remove(sibling.Element);
}
}
finally
{
_internalUpdate = false;
}
}
