private void OnRootLoaded()
{
// The following assumptions are made:
// 1. The visual structure of each TreeViewItem is the same regardless of its location.
// 2. The control template of a TreeViewItem contains ItemsPresenter.
ProperTreeViewItem root = _pendingRoot;
_pendingRoot = null;
root.Loaded -= OnRootLoaded;
ItemsPresenter itemsPresenter = null;
VisualTreeHelper2.EnumerateTree(root, null,
delegate(object visual, object misc)
{
itemsPresenter = visual as ItemsPresenter;
if (itemsPresenter != null && itemsPresenter.TemplatedParent == root)
{
return(HitTestResultBehavior.Stop);
}
else
{
itemsPresenter = null;
return(HitTestResultBehavior.Continue);
}
},
null);
if (itemsPresenter != null)
{
int levelLayoutDepth = 2;
DependencyObject tmp = itemsPresenter;
while (tmp != root)
{
++levelLayoutDepth;
tmp = VisualTreeHelper.GetParent(tmp);
}
int rootLayoutDepth = 0;
while (tmp != null)
{
++rootLayoutDepth;
tmp = VisualTreeHelper.GetParent(tmp);
}
_maxDepth = (200 - rootLayoutDepth) / levelLayoutDepth;
_rootItem = new WeakReference((VisualTreeItem)root.DataContext);
}
}
public bool ApplyReduceDepthFilterIfNeeded(ProperTreeViewItem curNode)
{
if (_pendingRoot != null)
{
OnRootLoaded();
}
if (_maxDepth == 0)
{
return(false);
}
VisualTreeItem rootItem = (VisualTreeItem)_rootItem.Target;
if (rootItem == null)
{
return(false);
}
if (_snoopUI == null)
{
_snoopUI = VisualTreeHelper2.GetAncestor <SnoopUI>(this);
if (_snoopUI == null)
{
return(false);
}
}
VisualTreeItem item = (VisualTreeItem)curNode.DataContext;
VisualTreeItem selectedItem = _snoopUI.CurrentSelection;
if (selectedItem != null && item.Depth < selectedItem.Depth)
{
item = selectedItem;
}
if ((item.Depth - rootItem.Depth) <= _maxDepth)
{
return(false);
}
for (int i = 0; i < _maxDepth; ++i)
{
item = item.Parent;
}
_snoopUI.ApplyReduceDepthFilter(item);
return(true);
}