<Window.Resources>
        <XmlDataProvider x:Key="myData" XPath="/Data">
            <x:XData x:Name="TT">
                <Data name="ROOT" xmlns="">
                    <Info name="root">
                        <InfoData value="qq" name="nn">
                            <Item name="имя 1" Type="Number"></Item>
                            <Item name="имя 2" Type="Number"></Item>
                        </InfoData>
                    </Info>     
                </Data>
            </x:XData>
        </XmlDataProvider>

        <HierarchicalDataTemplate DataType="Info" ItemsSource ="{Binding XPath=InfoData}">
            <TextBlock Text="{Binding XPath=@name}" />
        </HierarchicalDataTemplate>
        <HierarchicalDataTemplate DataType="InfoData" ItemsSource ="{Binding XPath=./*}">
            <TextBlock Text="{Binding XPath=@name}" />
        </HierarchicalDataTemplate>
        <HierarchicalDataTemplate DataType="Item" ItemsSource ="{Binding XPath=./*}">
            <TextBlock Text="{Binding XPath=@name}" />
        </HierarchicalDataTemplate>
    </Window.Resources>
    
    <Grid>
        <TreeView  Name="tv"  Margin="5,5,374,5" ItemsSource="{Binding Source={StaticResource myData}, XPath=Info}" />
        <Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="135,31,0,0" Name="button1" VerticalAlignment="Top" Width="75" Click="button1_Click" />
    </Grid>