IronPython & Silverlight Part VI: Using the TreeView control

In this post I'm going to show a small example of using the Silverlight 4 TreeView control with IronPython.

Referencing System.Windows.Controls.dll

Before we start using the TreeView control we need to add a reference to System.Windows.Controls.dll . This assembly can be found in the "Microsoft Silverlight 4 Tools for Visual Studio 2010" package.

You need to copy this assembly to the location of chiron.exe (ex. IronPython2.7\Silverlight\bin) and add a reference to it in the AppManifest.xaml file.

<Deployment xmlns="http://schemas.microsoft.com/client/2007/deployment" 
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
            RuntimeVersion="4.0.50917.0" 
            EntryPointAssembly="Microsoft.Scripting.Silverlight"  
            EntryPointType="Microsoft.Scripting.Silverlight.DynamicApplication" 
            ExternalCallersFromCrossDomain="ScriptableOnly">
  <!-- Add assembly references here -->
  <Deployment.Parts>
... 
    <AssemblyPart Source="System.Windows.Controls.dll" />
  </Deployment.Parts>
...
</Deployment>

Since we're using Silverlight 4 we need to change the runtime version to "4.0.50917.0" (see this post for more details).

Using the TreeView in XAML

Now that we have access to the assembly we can use it in app.xaml.

<UserControl x:Class="System.Windows.Controls.UserControl"
 xmlns="http://schemas.microsoft.com/client/2007"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:sdk="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"
        xmlns:wsdk="clr-namespace:System.Windows;assembly=System.Windows.Controls">
  <StackPanel x:Name="layout_root" Background="White">
    <TextBlock x:Name="Message" FontSize="30" Text="TreeView experiment" />
    <sdk:TreeView x:Name="tree">
       <sdk:TreeView.ItemTemplate>
           <wsdk:HierarchicalDataTemplate ItemsSource="{Binding nodes}">
               <TextBlock Foreground="Red" Text="{Binding label}" />
           </wsdk:HierarchicalDataTemplate>
       </sdk:TreeView.ItemTemplate>
    </sdk:TreeView>
  </StackPanel>
</UserControl>

TreeView data binding

The XAML file above shows that we're binding the content of the tree view to the nodes property of the data source object. Here's the definition of the Python class used for this example:

from System.Windows import Application
from System.Windows.Controls import UserControl
from System import Object
from System.Collections.ObjectModel import ObservableCollection
import clrtype
import clr

clr.AddReferenceToFile('GalaSoft.MvvmLight.SL4.dll')

from GalaSoft.MvvmLight.Command import RelayCommand


class Node:
  __metaclass__ = clrtype.ClrClass
  __clrnamespace = "LangexplrExperiments"


  def __init__(self,label,children):
    self.text = label
    self.children = children

  @property 
  @clrtype.accepts()
  @clrtype.returns(str)
  def label(self): 
     return self.text

  @property 
  @clrtype.accepts()
  @clrtype.returns(Object)
  def nodes(self): 
     return self.children



class App:
  def __init__(self):
    root = Application.Current.LoadRootVisual(UserControl(), "app.xaml")
    root.tree.ItemsSource = [Node('level1',
                                 [Node('level11',[]),
                                  Node('level12',[Node('level121',[])])
                                 ])]


App()

With this changes we can run chiron.exe /b and we get: