<Window x:Class="TeleTree.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
        mc:Ignorable="d" 
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="350" Width="525">
    <Grid>
        <telerik:RadTreeListView x:Name="radTreeListView" AutoGenerateColumns="False" IsReadOnly="True">
            
            <telerik:RadTreeListView.ChildTableDefinitions>
                <telerik:TreeListViewTableDefinition ItemsSource="{Binding Children}" />
            </telerik:RadTreeListView.ChildTableDefinitions>
            
            <telerik:RadTreeListView.Columns>
                <telerik:GridViewToggleRowDetailsColumn/>
                <telerik:GridViewDataColumn  DataMemberBinding="{Binding Name}" Header="Name" Width="100"/>
            </telerik:RadTreeListView.Columns>
            
            <telerik:RadTreeListView.RowDetailsTemplate>
                <DataTemplate>
                    <Grid x:Name="DetailGrid">
                        <StackPanel Orientation="Horizontal" Margin="0" Visibility="Collapsed">
                            <TextBlock Text="Type:"/>
                            <TextBox Text="{Binding Type}"/>
                        </StackPanel>
                    </Grid>
                    <DataTemplate.Triggers>
                        <DataTrigger Binding="{Binding Type}" Value="Leaf">
                            <Setter TargetName="DetailGrid" Property="Visibility" Value="Visible" />
                        </DataTrigger>
                    </DataTemplate.Triggers>
                </DataTemplate>
            </telerik:RadTreeListView.RowDetailsTemplate>
        </telerik:RadTreeListView>
    </Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
 
namespace TeleTree
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            this.radTreeListView.ItemsSource = DataService.GetData();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections.ObjectModel;
 
namespace TeleTree
{
    public class Node
    {
        public List<Node> Children = new List<Node>();
        public string Name;
        public string Type;
        
    }
 
    public class DataService
    {
        public static ObservableCollection<Node> GetData()
        {
            ObservableCollection<Node> list = new ObservableCollection<Node>();
 
            Node node1 = new Node()
            {
                Name = "Node1",
                Type = "Node"                
            };
 
            Node node1_1 = new Node()
            {
                Name = "Node1_1",
                Type = "Leaf"
            };
 
            Node node2 = new Node()
            {
                Name = "Node2",
                Type = "Node"
            };
 
            Node node2_2 = new Node()
            {
                Name = "Node2_2",
                Type = "Leaf"
            };
 
            node1.Children.Add(node1_1);
            node2.Children.Add(node2_2);
            list.Add(node1);
            list.Add(node2);
            return list;
        }
    }
}