WPF: Problem with TreeView databinding

I have a tree view defined as follows:

<HierarchicalDataTemplate x:Key="ChildTemplate"
                          ItemsSource="{Binding Children}">
    <TextBlock Text="{Binding TagName, Mode=OneWay}"/>
</HierarchicalDataTemplate>
<HierarchicalDataTemplate x:Key="NavigationHeaderTemplate"
                          ItemsSource="{Binding Children}"
                          ItemTemplate="{StaticResource ChildTemplate}">
    <StackPanel Orientation="Horizontal" Margin="0">
        <Image Source="{Binding Image}" Height="16" Width="16"></Image>
        <TextBlock Text="{Binding Header}"></TextBlock>
    </StackPanel>
</HierarchicalDataTemplate>
<TreeView Grid.Row="0" Grid.Column="0" Margin="0"
    FlowDirection="LeftToRight"
    ItemTemplate="{StaticResource NavigationHeaderTemplate}"
    Name="TreeView2">
</TreeView>

The data binding is:

public class ViewTag : INotifyPropertyChanged
{
    private string _tagName;
    public string TagName
    {
        get { return _tagName; }
        set
        {
            _tagName = value;
            PropertyChanged(this, new PropertyChangedEventArgs("Tag Name"));
        }
    }
    private ObservableCollection<ViewTag> _childTags;
    public ObservableCollection<ViewTag> ChildTags
    {
        get { return _childTags; }
        set
        {
            _childTags = value;
            OnPropertyChanged(new PropertyChangedEventArgs("Child Tags"));
        }
    }

    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;
    public void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, e);
    }
    #endregion

    public ViewTag(string tagName, ObservableCollection<ViewTag> childTags)
    {
        _tagName = tagName;
        _childTags = childTags;
    }
}

public class ViewNavigationTree
{
    public string Image { get; set; }
    public string Header { get; set; }
    public ObservableCollection<ViewTag> Children { get; set; }
}

And my test binding is:

        var xy = new List<ViewNavigationTree>();
        List<ViewTag> tempTags = new List<ViewTag>();
        ViewTag t1, t2, t3, t4, t5, t6;
        t1 = new ViewTag("Computers", null);
        t2 = new ViewTag("Chemistry", null);
        t3 = new ViewTag("Physics", null);
        var t123 = new ObservableCollection<ViewTag>();
        t123.Add(t1);
        t123.Add(t2);
        t123.Add(t3);
        t4 = new ViewTag("Science", t123);
        var t1234 = new ObservableCollection<ViewTag>();
        t1234.Add(t4);
        t5 = new ViewTag("All Items", t1234);
        t6 = new ViewTag("Untagged", null);

        var tall = new ObservableCollection<ViewTag>();
        tall.Add(t5);
        tall.Add(t6);
        xy.Add(new ViewNavigationTree() { Header = "Tags", Image = "img/tags2.ico", Children = tall });

        var rootFolders = eDataAccessLayer.RepositoryFacrory.Instance.MonitoredDirectoriesRepository.Directories.ToList();
        var viewFolders = new ObservableCollection<ViewTag>();
        foreach (var vf in rootFolders)
        {
            viewFolders.Add(new ViewTag(vf.FullPath, null));
        }
        xy.Add(new ViewNavigationTree() { Header = "Folders", Image = "img/folder_16x16.png", Children = viewFolders });

        xy.Add(new ViewNavigationTree() { Header = "Authors", Image = "img/user_16x16.png", Children = null });
        xy.Add(new ViewNavigationTree() { Header = "Publishers", Image = "img/powerplant_32.png", Children = null });

        TreeView2.ItemsSource = xy开发者_运维技巧;

Problem is, the tree only shows:

+ Tags
    All Items
    Untagged
+ Folders
    dir 1
    dir 2
    ...
Authors
Publishers

The items I added under "All Items" aren't displayed.

Being a WPF nub, i can't put my finger on the problem. Any help will be greatly appriciated.

The only thing that jumps out here is that you're referencing the Children property in your ChildTemplate instead of ChildTags as defined in ViewTag.

For TreeView binding, you need to use a HierarchicalDataTemplate. This allows you to specify both the data for the node, and also the children for the node (by binding to ItemsSource).