Get TreeViewItem for TreeView logical element

Question

My tree view seems like this

Answer 1

if I got you correctly you want to retrieve the TreeViewItem from the SelectedItem

so you can make use of ItemContainerGenerator

        ItemContainerGenerator gen = ArticlesTreeView.ItemContainerGenerator;
        TreeViewItem item = gen.ContainerFromItem(ArticlesTreeView.SelectedItem) as TreeViewItem;

Get TreeViewItem from nested items

due to the reason that every TreeViewItem has it's own ItemContainerGenerator so in order to find the container from the nested items we need to recurse the depth of the tree

    private void ArticlesTreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
    {
        var item = ContainerFromItem(ArticlesTreeView.ItemContainerGenerator, ArticlesTreeView.SelectedItem);
    }

    private static TreeViewItem ContainerFromItem(ItemContainerGenerator containerGenerator, object item)
    {
        TreeViewItem container = (TreeViewItem)containerGenerator.ContainerFromItem(item);
        if (container != null)
            return container;

        foreach (object childItem in containerGenerator.Items)
        {
            TreeViewItem parent = containerGenerator.ContainerFromItem(childItem) as TreeViewItem;
            if (parent == null)
                continue;

            container = parent.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItem;
            if (container != null)
                return container;

            container = ContainerFromItem(parent.ItemContainerGenerator, item);
            if (container != null)
                return container;
        }
        return null;
    }