TreeView, HierarchicalDataTemplate and recursive Data

Question

For my treeview I have two different classes that provide the ItemsSource.

public class TreeViewModel : ViewModelBase
{
    public ObservableCollection

        

Answer 1

You should only have to declare the HierarchicalDataTemplate for NodeViewModel as this is the only thing showing in the TreeView, and bind the actual ItemSource to the TreeView

Full Example

Xaml:

Code:

public partial class MainWindow : Window
{

    public MainWindow()
    {
        InitializeComponent();
    }

    public TreeViewModel TreeModel
    {
        get
        {
            return new TreeViewModel
            {
                Items = new ObservableCollection{
                           new NodeViewModel { Name = "Root", Children =  new ObservableCollection {
                              new NodeViewModel { Name = "Level1" ,  Children = new ObservableCollection{ 
                                  new NodeViewModel{ Name = "Level2"}}} } }}
            };
        }
    }
}

public class TreeViewModel
{
    public ObservableCollection Items { get; set; }
}

public class NodeViewModel
{
    public string Id { get; set; }
    public string Name { get; set; }
    public ObservableCollection Children { get; set; }
}

Result: