public class Pair<T, U>
    {
        public Pair()
        {
        }

        public Pair(T first, U second)
        {
            this.First = first;
            this.Second = second;
        }

        public T First { get; set; }
        public U Second { get; set; }
    };

    sealed class Dumper
    {
        static public string Dump(Node root)
        {
            StringBuilder fulltree = new StringBuilder();
            if (root == null)
                return string.Empty;
            fulltree.Append(root.Text + "\n");

            Stack<Pair<int, IList<Node>>> browser = new Stack<Pair<int, IList<Node>>>();
            browser.Push(new Pair<int, IList<Node>>(0, root.Children));

            // customize tree
            const string branch = "├", lastbranch = "└", vertical = "│", space = " ", horizontal = "─";
            List<string> currPath = new List<string>();

            // for each list of children
            while (browser.Count != 0)
            {
                Pair<int, IList<Node>> current = browser.Peek();
                if (current.First >= current.Second.Count)
                {
                    // stop!
                    browser.Pop();
                    if (currPath.Count > 0)
                        currPath.RemoveAt(currPath.Count - 1);
                }
                else
                {
                    if ((current.First + 1) == current.Second.Count)
                    {
                        Node n = current.Second[current.First];
                        string path = string.Join(space, currPath.ToArray());
                        if (!string.IsNullOrEmpty(path))
                            path += space;
                        fulltree.Append(path + lastbranch + horizontal + n.Text + "\n");
                        
                        if (n.Children.Count > 0)
                        {
                            currPath.Add(space);
                            browser.Push(new Pair<int, IList<Node>>(0, n.Children));
                        }
                    }
                    else
                    {
                        Node n = current.Second[current.First];
                        string path = string.Join(space, currPath.ToArray());
                        if (!string.IsNullOrEmpty(path))
                            path += space;
                        fulltree.Append(path + branch + horizontal + n.Text + "\n");
                        if (n.Children.Count > 0)
                        {
                            browser.Push(new Pair<int, IList<Node>>(0, n.Children));
                            currPath.Add(vertical);
                        }
                    }
                    current.First++;
                }
            }
            return fulltree.ToString();
        }
    }