Distributing Silverlight application written in IronPython

When you have Silverlight application written in IronPython, it is a good idea to split it to several files so browser can cache them separately. Later, when you change something in your application, users will download only a small part. During my attemts with IronPython and Silverligt, I have found several catches. That's why I describe here my way how to distribute IronPython Silverlight application.

I distribute my application as one .html file, one .xap file, and several .zip files. I use .zip because IIS already knows what to do with .zip files. The files are:

1. index.html
2. app.xap
3. IronPython.zip - contains files from IronPython-2.6.1\Silverlight\bin:

   IronPython.dll
   IronPython.Modules.dll
   

4. Microsoft.Scripting.zip - contains files from IronPython-2.6.1\Silverlight\bin:

   Microsoft.Dynamic.dll
   Microsoft.Scripting.dll
   Microsoft.Scripting.Core.dll
   Microsoft.Scripting.ExtensionAttribute.dll
   Microsoft.Scripting.Silverlight.dll
   

5. SLToolkit.zip - contains files form Silverlight toolkit or SDK; in our case just

System.Windows.Controls.dll

Let's create a small application, that uses ChildWindow control from Silverlight toolkit:

C:\IronPython-2.6.1\Silverlight\script\sl.bat python childwindow

Change the app.py and app.xml:

app.py

from System.Windows import Application
from System.Windows.Controls import UserControl

class App:
    def __init__(self):
        self.root = Application.Current.LoadRootVisual(UserControl(), "app.xaml")

a = App()

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:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls">
  <controls:ChildWindow >
    <StackPanel>
      <TextBlock Text="Text in ChildWindow"/>
      <Button x:Name="btnNewWindow" Content="New window"/>
    </StackPanel>
  </controls:ChildWindow>
</UserControl>

We don't want to Chiron automatically add necesary .dll files into .xap so we have to add our own AppManifest.xaml and languages.config into childwindow\app folder:

AppManifest.xaml

<Deployment xmlns="http://schemas.microsoft.com/client/2007/deployment"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  RuntimeVersion="2.0.31005.0"
  EntryPointAssembly="Microsoft.Scripting.Silverlight"
  EntryPointType="Microsoft.Scripting.Silverlight.DynamicApplication"
  ExternalCallersFromCrossDomain="ScriptableOnly">
  <Deployment.Parts>
  </Deployment.Parts>
  <Deployment.ExternalParts>
    <ExtensionPart Source="Microsoft.Scripting.zip" />
    <ExtensionPart Source="SLToolkit.zip" />
  </Deployment.ExternalParts>
</Deployment>

languages.config

<Languages>
  <Language names="IronPython,Python,py"
    languageContext="IronPython.Runtime.PythonContext"
    extensions=".py"
    assemblies="IronPython.dll;IronPython.Modules.dll"
    external="IronPython.zip"/>
</Languages>

Now create all three .zip files and add them into childwindow folder.

To test the application with Chiron, run

C:\IronPython-2.6.1\Silverlight\bin\Chiron.exe /e: /d:childwindow

The /e: switch is important - it tells Chiron to not put any assembly into generated .xap file. Check the application on http://localhost:2060/index.html.

To generate .xap file for distribution, run:

C:\IronPython-2.6.1\Silverlight\bin\Chiron.exe /e: /d:childwindow\app /z:app.zap

If you want to use anything from external assemblies in the code, you have to add manually reference to those assemblies. For example, if you want to add a button that creates a new ChildWindow, you have to change you code like this:

app.py

from System.Windows import Application
from System.Windows.Controls import UserControl

class App:
    def __init__(self):
        self.root = Application.Current.LoadRootVisual(UserControl(), "app.xaml")
        self.root.btnNewWindow.Click += self.OnClick

    def OnClick(self, sender, event):
        import clr
        clr.AddReference('System.Windows.Controls')
        from System.Windows.Controls import ChildWindow
        self.root.panel.Children.Add(ChildWindow(Content='new window'))

a = App()

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:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls">
  <controls:ChildWindow >
    <StackPanel x:Name="panel">
      <TextBlock Text="Text in ChildWindow"/>
      <Button x:Name="btnNewWindow" Content="New window"/>
    </StackPanel>
  </controls:ChildWindow>
</UserControl>

If you comment out the clr.AddReference line, ImportError appears. See the explanation in Jimmy's email.

You can download the example here but note the .zip files do not contain and .dlls.

Silverlight validation with IronPython

Validation support in Silverlight is done via Visual State Manager. All invalid fields have red rectangle around themselves. Unfortunately, this does not work out of the box in IronPython. We have to push it a little bit.

To demonstrate how, I have created a small example. Create a Silverlight app template and change app.py and app.xaml:

C:\IronPython-2.6.1\Silverlight\script\sl.bat python validation

app.py

import clrtype
import pyevent
from System.Windows import Application
from System.Windows.Controls import UserControl
from System.ComponentModel import INotifyPropertyChanged, PropertyChangedEventArgs

class ValidationClass(INotifyPropertyChanged):
    __metaclass__ = clrtype.ClrClass
    PropertyChanged = None

    def __init__(self, win):
        self.win = win
        self._text = 'text'
        self.PropertyChanged, self._propertyChangedCaller = pyevent.make_event()

    def add_PropertyChanged(self, value):
        self.PropertyChanged += value

    def remove_PropertyChanged(self, value):
        self.PropertyChanged -= value

    def OnPropertyChanged(self, propertyName):
        if self.PropertyChanged is not None:
            self._propertyChangedCaller(self, PropertyChangedEventArgs(propertyName))

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

    @text.setter
    @clrtype.accepts(str)
    @clrtype.returns()
    def text(self, value):
        if not value.startswith('text'):
            raise Exception('Value must start with text!')
        self._text = value
        self.OnPropertyChanged('text')

class App:
    def __init__(self):
        self.root = Application.Current.LoadRootVisual(UserControl(), "app.xaml")
        self.root.DataContext = ValidationClass(self.root)

App()

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">
  <StackPanel>
    <TextBox x:Name="tbValidate1" Width="100" Height="25" 
      Text="{Binding text, Mode=TwoWay, ValidatesOnExceptions=True,
      NotifyOnValidationError=True}" />
    <TextBox Width="100" Height="25" />
    <TextBlock Text="{Binding text}" HorizontalAlignment="Center" />
  </StackPanel>
</UserControl>

When you run this application (C:\IronPython-2.6.1\Silverlight\script\server.bat /d:validation), you'll find out the validation does not work. There is no red rectangle when you enter wrong value; e.g. wrong.

Note the second empty TextBox is there so you can move focus out of the first one to update bound property.

For whatever reason, the invalid component is not switched into invalid state. Could be IronPython bug, could be something else. Anyway to fix it, you have to switch the control into invalid state manually. Add the BindingValidationError event:

from System.Windows import VisualStateManager
from System.Windows.Controls import ValidationErrorEventAction

...

class App:
    def __init__(self):
        self.root = Application.Current.LoadRootVisual(UserControl(), "app.xaml")
        self.root.DataContext = ValidationClass(self.root)
        self.root.BindingValidationError += self.OnBindingValidationError

    def OnBindingValidationError(self, sender, event):
        if event.Action == ValidationErrorEventAction.Added:
            VisualStateManager.GoToState(event.OriginalSource, 'InvalidUnfocused', True)
        else:
            VisualStateManager.GoToState(event.OriginalSource, 'Valid', True

Now when you enter wrong value into TextBox, you can see red rectangle around the control. You also see, the bound variable has the old, correct value text:

You can download the whole source here.