如何查看扩展TreeViewItem的所有TreeViewItems

public static class TreeViewItemExtensions
{
    public static IEnumerable<TreeViewItem> GetAllTreeViewItems(this TreeViewItem item)
    {
        yield return item;

        if (item.Items.Count > 0)
        {
            foreach (var subItem in item.Items)
            {
                if (subItem is TreeViewItem subTreeViewItem)
                {
                    foreach (var subSubItem in subTreeViewItem.GetAllTreeViewItems())
                    {
                        yield return subSubItem;
                    }
                }
            }
        }
    }
}

ExtendedTreeViewItem extendedTreeViewItem = new ExtendedTreeViewItem();
// 添加子TreeViewItems到extendedTreeViewItem

foreach (var treeViewItem in extendedTreeViewItem.GetAllTreeViewItems())
{
    // 处理每个TreeViewItem
}