void BindTreeViewItem(VisualElement element, int index) { var visualProgressItem = element as VisualProgressItem; if (visualProgressItem == null) { return; } var progressItem = m_TreeView.GetItemDataForIndex <Progress.Item>(index); visualProgressItem.BindItem(progressItem); var indentLevel = GetIndentationLevel(index); var rootVE = m_TreeView.GetRootElementForIndex(index); var isEven = indentLevel % 2 == 0; rootVE.EnableInClassList("unity-tree-view__item-indent-even", isEven); rootVE.EnableInClassList("unity-tree-view__item-indent-odd", !isEven); }