Binding to TreeView in WPF

Question

I am trying to bind some data from a class instance to a TreeView. My code is as follows:

public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); Parent myClass = new Parent(); this.DataContext = myClass; } } public class Parent { private List<string> children = new List<string>; public string Name {get;set;} public List<string> Children { get { return this.children; } set { this.children=value; } } public Parent() { this.Name = "Test"; for (int i = 1; i <= 10; i++) { Children.Add(i.ToString()); } } }

And the XAML:

<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:loc="clr-namespace:WpfApplication1" Title="MainWindow" Height="287" Width="525"> <StackPanel Orientation="Horizontal" VerticalAlignment="Stretch"> <TreeView Name="TreeView" ItemsSource="{Binding}"> <TreeView.ItemTemplate> <HierarchicalDataTemplate ItemsSource="{Binding Children}"> <TextBlock Text="{Binding Name}"/> </HierarchicalDataTemplate> </TreeView.ItemTemplate> </TreeView> </StackPanel> </Window>

Nothing shows up in my TreeView. What am I doing wrong?

I expect to see:

-Test
-- 1
-- 2
-- 3
etc

updated: to make Name and Children properties instead of public fields.
updated: added what I expect to see in TreeView

apandit · Accepted Answer · 2010-03-24 15:46:28Z

You bind "myClass" of type Parent to the datacontext and use the same object for the ItemSource. This won't work because Parent is not an enumerable type.

Change your ItemSource binding from "{Binding}" to "{Binding Children}" and change your HierarchicalDataTemplate to just a DataTemplate.

If you want to retain myClass as a top level node, you could also wrap myclass in an IEnumerable and set that as the data context.

In this case, how would I get the Parent.Name to show up as the top level node? This is what I want to see: -Test --1 --2 --3 --4 etc
Create a list of type Parent and add myclass to it. Then, set the datacontext to the list instead of the object.

Charlie · Accepted Answer · 2010-03-24 15:20:38Z

0

You can only bind to public properties, not fields. Change Name and Children to be public properties and this should work.

answered Mar 24, 2010 at 15:20

Charlie

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1 Comment

KrisTrip Over a year ago

Made this update (shown in original question) and nothing changed. TreeView is still empty.

VoidDweller · Accepted Answer · 2010-03-24 16:03:49Z

Here try this:

 <StackPanel Orientation="Horizontal" VerticalAlignment="Stretch"> <TextBlock Text="{Binding Name}"/> <TreeView Name="TreeView" ItemsSource="{Binding Children}"> <TreeView.ItemTemplate> <HierarchicalDataTemplate ItemsSource="{Binding Children}"> <TextBlock Text="{Binding}"/> </HierarchicalDataTemplate> </TreeView.ItemTemplate> </TreeView> </StackPanel>

A few things:

The 'Name' Property was out of scope.
We need to bind the TreeView as well as the DataTemplate
We use the default {Binding} to call ToString() on the current item.

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