public void ExpandBones(IList <int> expandedIds, IList <TreeViewItem> items) { var expandedBones = items.Where(x => expandedIds.Contains(x.id)).Select(y => ((TreeViewItemBase <BoneCache>)y).customData).ToArray(); using (m_Model.UndoScope(TextContent.expandBones)) { m_Model.SetExpandedBones(expandedBones); } }