Adding UIA support for ScrollBar

[SergeySmirnov-Akvelon]

Fixes #4983

Proposed changes

• Updated "SupportsUiaProviders" flag.
• Added and implemented ScrollBar accessible objects
• Added unit tests

Customer Impact

Before fix:

Accessibility providers:
[pid:10384,providerId:0x811196 Main:Nested [pid:10832,providerId:0x811196 Main(parent link):Microsoft: MSAA Proxy (unmanaged:UIAutomationCore.dll)]; Hwnd(parent link):Microsoft: HWND Proxy (unmanaged:uiautomationcore.dll)]

Afrer fix:

Accessibility providers:
[pid:30620,providerId:0xD1472 Main:Nested [pid:52468,providerId:0xD1472 Main(parent link):Unidentified Provider (unmanaged:coreclr.dll)]; Hwnd(parent link):Microsoft: HWND Proxy (unmanaged:uiautomationcore.dll)]

Regression?

• No

Risk

• Minimal

Test methodology

• Unit tests
• CTI team

Accessibility testing

• Narrator
• Inspect
• Accessibility Insights

Test environment(s)

• Microsoft Windows [Version 10.0.19041.388]
• .NET Core SDK: 6.0.100-preview.3.21202.5

Microsoft Reviewers: Open in CodeFlow

[RussKie]

Similar comments as for #4939

[Tanya-Solyanik]

added some questions about Enabled UIA property.

[RussKie]

Forgot to clean or push?

Also make sure it runs locally:

    System.Windows.Forms.Maui.IntegrationTests.WinformsMauiVScrollBarTests.MauiVScrollBarTests [FAIL]
      System.IO.FileNotFoundException : File does not exist
      Stack Trace:
        /_/src/System.Windows.Forms/tests/IntegrationTests/System.Windows.Forms.IntegrationTests.Common/TestHelpers.cs(53,0): at System.Windows.Forms.IntegrationTests.Common.TestHelpers.GetExePath(String projectName)
        /_/src/System.Windows.Forms/tests/IntegrationTests/System.Windows.Forms.Maui.IntegrationTests/MauiTestHelper.cs(40,0): at System.Windows.Forms.Maui.IntegrationTests.MauiTestHelper.GetScenarios(String projectName)
        /_/src/System.Windows.Forms/tests/IntegrationTests/System.Windows.Forms.Maui.IntegrationTests/MauiDataAttribute.cs(55,0): at System.Windows.Forms.Maui.IntegrationTests.MauiDataAttribute.GetData(MethodInfo testMethod)

[Tanya-Solyanik]

Is IsDisplayed test copied from the previous implementation?

Is it possible to Invoke this object in the previous implementation when this button is not displayed?

[SergeySmirnov-Akvelon]

In this case, the IsDisplayed flag, in addition to the fact that the element is invisible, means that the trackbar already has a minimum/maximum value and calling the Invoke method for element will not lead to any action.

[Tanya-Solyanik]

Could you please share an image of visual element that owns this accessible object?

IsDisplayed property seems to be very similar to Enabled, but I don't see why we would not want to navigate from a disabled element to its siblings....

How is navigation handled by the MSAA proxy?

[SergeySmirnov-Akvelon]

I have investigated this case and found that if the element is invisible, than FragmentNavigate(NavigateDirection.Parent) method returns Parent correctly, but FragmentNavigate(NavigateDirection.NextSibling) and FragmentNavigate(NavigateDirection.PreviousSibling) methods return null value.

I fixed this case for ScrollBar and updated the tests. I also fixed this case for TrackBar.

The IsDisplayed property means that the ScrollBar has a minimum / maximum value. Therefore this element is invisible and does not require user interaction.

[Tanya-Solyanik]

@DmitryGorokhov - see the before/after screenshots and red/green highlights to see when MSAA proxy is used and when our custom providers are

[dreddy-work]

@Olina-Zhang

[SergeySmirnov-Akvelon]

Approved by CTI team