Hierarchical binding WPF TreeView.

just starting with wpf. I need to link an object (Hierarchical) Folder

public class Folder
{
    public Folder()
    {
        this.Name = string.Empty;
        this.Modules = new ObservableCollection<Module>();
        this.Folders = new List<Folder>();
        this.HasChild = false;
    }

    public Folder(Folder parent)
    {
        this.Name = string.Empty;
        this.Modules = new ObservableCollection<Module>();
        this.Folders = new List<Folder>();
        this.HasChild = false;
        this.Parent = parent;
    }

    public bool HasChild { get; set; }

    public string Name { get; set; }

    public List<Folder> Folders { get; set; }

    public ObservableCollection<Module> Modules { get; set; }

    public Folder Parent { get; set; }

    public Folder IfItemExists(string name)
    {
        foreach (Folder folder in Folders)
        {
            if (folder.Name == name)
            {
                return folder;
            }
        }

        return null;
    }
}

for wood. I do like this

   <TreeView Name="treeView" Margin="5">
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Path=Folders}" DataType="{x:Type ModulesUpToDateChecker:Folder}">
                <HierarchicalDataTemplate.ItemTemplate>
                    <DataTemplate>
                        <TextBlock Text="{Binding Path=Name}"></TextBlock>
                    </DataTemplate>
                </HierarchicalDataTemplate.ItemTemplate>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

and have only an empty docpanel. The object is filled with a letter. An Eche child has his own child with the same type.