Load XmlDocument to XmlDataProvider

   
  

<Window x:Class="WpfApplication1.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WpfApplication1"
    Title="Window1" Height="400" Width="600" Loaded="Window_Loaded" Name="window">
    <Window.Resources>
        <XmlDataProvider x:Key="xaml" />
    </Window.Resources>
    <StackPanel>
        <TreeView Name="treeView1" ItemsSource="{Binding Source={StaticResource xaml}, XPath=*}">
            <TreeView.ItemTemplate>
                <HierarchicalDataTemplate ItemsSource="{Binding XPath=*}">
                    <TextBlock Text="{Binding Path=Name}" />
                </HierarchicalDataTemplate>
            </TreeView.ItemTemplate>
        </TreeView>
        <TextBox Text="{Binding ElementName=treeView1, Path=SelectedItem.OuterXml, Mode=OneWay}" TextWrapping="Wrap" />
    </StackPanel>
</Window>
//File:Window.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.IO;
using System.Windows.Markup;
using System.Xml;

namespace WpfApplication1
{
    public partial class Window1 : Window
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            string xaml = XamlWriter.Save(this);

            XmlDocument doc = new XmlDocument();
            doc.LoadXml(xaml);

            XmlDataProvider provider = (XmlDataProvider)FindResource("xaml");
            provider.Document = doc;
            provider.Refresh();
        }
    }
}