MVVM tree

Start new WPF application. Add TreeView control from toolbox.
Add one label.
My XAML looks like this:

<Window x:Class="MVVMtreeView.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TreeView HorizontalAlignment="Left" Height="206" Margin="10,10,0,0" VerticalAlignment="Top" Width="497"/>
        <Label Content="Label" HorizontalAlignment="Left" Margin="10,284,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.421,0.462" Width="497"/>

    </Grid>
</Window>

Then add model, I called it TreeViewModel, and it looks like this:

namespace MVVMtreeView
{
    public class TreeViewModel
    {
        public List<string> TreeViewModels { get; set; }

        public TreeViewModel()
        {
            TreeViewModels = new List<string>();
            TreeViewModels.Add("test");
        }
    }
}

In "code behind", in MainWindow.xaml.cs, in MainWindow method, add line DataContext = new TreeViewModel(); so, in my case MainWindow.xaml.cs looks like this:

namespace MVVMtreeView
{
    /// 
    /// Interaction logic for MainWindow.xaml
    /// 
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext = new TreeViewModel();
        }
    }
}

Now, bind tree view to a model, that means in the XAML (in my case MainWindow.xaml), add ItemsSource="{Binding Path=TreeViewModels}", I also add name to a tree view, then bind label content, so now my XAML looks like this:

<Window x:Class="MVVMtreeView.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <TreeView Name="tv" ItemsSource="{Binding Path=TreeViewModels}"  HorizontalAlignment="Left" Height="206" Margin="10,10,0,0" VerticalAlignment="Top" Width="497"/>
        <Label Content="{Binding ElementName=tv, Path=SelectedItem}" HorizontalAlignment="Left" Margin="10,284,0,0" VerticalAlignment="Top" RenderTransformOrigin="0.421,0.462" Width="497"/>

    </Grid>
</Window>

Example you can download from here.