Accessibility: Moonlight Sandbox

Table of contents

Moonlight Sandbox

This is a space to collect ideas about the Moonlight work for Phase 2.

Tasks for Research Week

We'll attack research week from three fronts:


  • Investigate the API that existing Microsoft Silverlight 2 providers use
    • Specifically, what standard System.Windows.Automation API needs to be implemented? What about System.Automation.Peers?
  • Determine what level of effort will be required to implement that API, or alternatively to adapt providers to use our existing API
  • What kind of integration will be necessary with the moon repo? Does moon need to depend on our uia2atk repository? If so, how will that work?
  • How much effort is required to complete the UIA providers for RuntimeControls?


  • A summary of your findings sent to the team via email. Additionally, an hour estimate for completing the Runtime Controls, and for any necessary API modifications.


  • Silverlight 2 is a subset of WPF and supports building complex user interfaces, so basically you can define flexible composite Controls, for example, a ListBox containing Grids, and those Grids containing StackPanels and those StackPanels containing Buttons, and so on.
  • Accessibility in SL2 is defined using AutomationPeers, there is an AutomationPeer for each control, for example ButtonAutomationPeer is used by ButtonControl.
  • Accessibility in SL2 is initialized automatically by Silverlight 2 by calling an overridden method: SWAP.AutomationPeer.OnCreateAutomationPeer, this method returns and instance that should not be destroyed until the associated control is disposed, same approach as in MonoUIAutomationWinforms.
  • AutomationPeer is not equal to IRawElementProviderSimple, however there's a method to cast from IRawElementProviderSimple: AutomationPeer.PeerFromProvider
  • There's a factory FrameworkElementAutomationPeer to create peers: CreatePeerForElement(UIElement), similar to ProviderFactory.GetProvider and SWAP.XXXXXPeer.FromElement(UIElement), similar to ProviderFactory.FindProvider.
  • Navigation is different, IRawElementProviderFragment doesn't exist, so there is no explicit sibling navigation, 2 methods replace IRawElementProviderFragment.Navigate: AutomationPeer.GetParent and AutomationPeer.GetChildren.
  • Patterns and properties implementation is similar, however due to attached properties in Silverlight we need to implement a new class: SWA.AutomationProperties (see table below) to support DependencyObject.GetValue/DependencyObject.SetValue.
  • There are some AutomationPeer classes already implemented (found in the Sample Source Code for Silverlight 2 Runtime and SDK Controls) however the core (primitives and simple controls) are not implemented in this source code.
API difference
.NET 3.5 Silverlight 2
Namespace System.Windows.Automation
-TextPattern +TextPattern
--- +AutomationProperties
UIAutomationTypes.dll System.Windows.dll
Namespace System.Windows.Automation.Peers
Doesn't not exist Must be implemented (Similar to MonoUIAutomationWinforms)
--- System.Windows.dll
Namespace System.Windows.Automation.Provider
--- Subset of .NET 3.5
UIAutomationProvider.dll System.Windows.dll
Automation Events
Using SWAProvider.AutomationInteropProvider.RaiseXXXXEvent methods Using SWAPeers.AutomationPeer.RaiseXXXXEvents methods



  • How should the bridge be loaded and integrate with the providers?
  • Where should the bridge reside so that it can be used by moon?
  • How do SL2 controls map to Atk.Roles? Will any additional bridge work be required to support the SL2 controls?


  • Email report with a plan for loading and integrating the bridge with the providers.
  • A list of SL2 controls and which Atk.Role they map to.
  • A high-level breakdown and ballpark hour estimate for any bridge customization required for the SL2 controls.

Plugin integration

  • How can a FF plugin inject an Atk.Object into the DOM tree?
  • How will the Bridge be distributed so that it can be used by the plugin?


  • Email to the team containing an hour estimate for integration, and a proposal for how it should be integrated and distributed.

Requirements for Moonlight development

  • mozilla-nspr-devel
  • mozilla-nss-devel
  • mozilla-xulrunner190-devel
  • ImageMagick-devel
  • libMagick++-devel
  • fetchmsttfonts, to avoid failures when running moon-unit (still using OpenSUSE 11? follow this)

Running the Moonlight 2.0 unit test suite

  • cd moon/test/
  • make install-test-plugin
  • make install-test
  • cd moon/test/2.0/moon-unit
  • make test