[Net11 Preview 6] WinUI: Document for CollectionViewHandler2 implementation

[SuthiYuvaraj]

Summary

In .NET 11, the Windows CollectionView implementation transitions to optimized default handlers, providing improved performance and stability.

This PR updates the CollectionView documentation to describe the handler-based implementation and provides an opt-out path for developers who need to continue using the previous handler behavior.

Related

MAUI PR: dotnet/maui#34600

Notes
Changes are scoped to the >= net-maui-11.0 moniker. Existing .NET 10 and earlier documentation remains unchanged.

Platform scope: Windows only.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

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[learn-build-service-prod]

Learn Build status updates of commit dbb91ef:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
docs/user-interface/controls/collectionview/index.md	⚠️Warning	View (>=net-maui-8.0)	Details
docs/whats-new/dotnet-11.md	✅Succeeded	View (>=net-maui-8.0)

docs/user-interface/controls/collectionview/index.md

• Line 19, Column 1: [Warning: moniker-zone-empty] No intersection between zone and file level monikers. The result of zone level range string 'net-maui-10.0 net-maui-11.0' is '', while file level monikers is 'net-maui-10.0', 'net-maui-11.0', 'net-maui-8.0', 'net-maui-9.0'.

For more details, please refer to the build report.

Note: Your PR may contain errors or warnings or suggestions unrelated to the files you changed. This happens when external dependencies like GitHub alias, Microsoft alias, cross repo links are updated. Please use these instructions to resolve them.

[Copilot]

Pull request overview

Documents the .NET 11 Preview 6 Windows CollectionView transition to the optimized (v2) default handlers and provides opt-out guidance, aligning the docs with the upstream MAUI change (dotnet/maui#34600).

Changes:

• Adds a .NET 11 “What’s New” entry describing Windows CollectionView v2 handlers and the UseWindowsCollectionView2Handler opt-out.
• Updates the CollectionView control docs with platform timing notes and opt-out options (code-based and MSBuild property).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
docs/whats-new/dotnet-11.md	Adds a Windows CollectionView v2 note and documents the UseWindowsCollectionView2Handler opt-out.
docs/user-interface/controls/collectionview/index.md	Updates handler-default timeline and opt-out guidance; adds Windows build-property opt-out.

[learn-build-service-prod]

Learn Build status updates of commit 03f7831:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/user-interface/controls/collectionview/index.md	✅Succeeded	View (>=net-maui-8.0)
docs/whats-new/dotnet-11.md	✅Succeeded	View (>=net-maui-8.0)

For more details, please refer to the build report.

[learn-build-service-prod]

Learn Build status updates of commit 2d3db73:

✅ Validation status: passed

File	Status	Preview URL	Details
docs/user-interface/controls/collectionview/index.md	✅Succeeded	View (>=net-maui-8.0)
docs/whats-new/dotnet-11.md	✅Succeeded	View (>=net-maui-8.0)

For more details, please refer to the build report.

[learn-build-service-prod]

PoliCheck Scan Report

The following report lists PoliCheck issues in PR files. Before you merge the PR, you must fix all severity-1 and severity-2 issues. The AI Review Details column lists suggestions for either removing or replacing the terms. If you find a false positive result, mention it in a PR comment and include this text: #policheck-false-positive. This feedback helps reduce false positives in future scans.

✅ No issues found

More information about PoliCheck

Information: PoliCheck | Severity Guidance | Term
For any questions: Try searching the learn.microsoft.com contributor guides or post your question in the Learn support channel.

[SuthiYuvaraj]

Closing this PR because the change has already been added in #3402.