Recursive lambda expression to traverse a tree in C#

Question

Can someone show me how to implement a recursive lambda expression to traverse a tree structure in C#.

Answer 1

Assuming a mythical object TreeItem, that conatins a Children collection to represent your hierarchy.

    public void HandleTreeItems(Action item, TreeItem parent)
    {
        if (parent.Children.Count > 0)
        {
            foreach (TreeItem ti in parent.Children)
            {
                HandleTreeItems(item, ti);
            }
        }

        item(parent);
    }

Now to call it, passing in the lambda that handles one item, by printing its name to the console.

HandleTreeItems(item => { Console.WriteLine(item.Name); }, TreeItemRoot);