[Windows] - Fix Grid layout not updating when Row/Column changed dynamically

[prakashKannanSf3972]

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Root Cause

• When Grid.Row or Grid.Column properties are updated on a Grid element nested within another Grid, the current implementation only invalidates the element itself and does not propagate the invalidation to its parent. As a result, the parent layout is not re-measured or arranged correctly, leading to inaccurate or incomplete rendering.

Description of Change

• Improved parent layout invalidation for Grid on Windows to ensure UI updates correctly when Grid.Row or Grid.Column properties change.

Issues Fixed

Fixes #20404

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Output

Before	After
BeforeFix_Grid.mp4	AfterFix_Grid.mp4

[dotnet-policy-service]

Hey there @@prakashKannanSf3972! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jsuarezruiz]

/azp run MAUI-UITests-public

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[Copilot]

Pull Request Overview

This PR ensures that dynamic changes to Grid.Row and Grid.Column on Windows correctly invalidate the parent layout so the UI updates without requiring a window resize.

• Added a UI sample page in the HostApp for toggling row/column at runtime.
• Added a cross-platform UI test in TestCases.Shared.Tests to verify dynamic grid updates.
• Updated Grid.cs to propagate measure invalidation to the parent grid on Windows.

Reviewed Changes

Copilot reviewed 3 out of 11 changed files in this pull request and generated 2 comments.

File	Description
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue20404.cs	New UITest verifying dynamic row/column toggles trigger layout updates.
src/Controls/tests/TestCases.HostApp/Issues/Issue20404.cs	New sample page with buttons to toggle grid row/column dynamically.
src/Controls/src/Core/Layout/Grid.cs	Updated Invalidate method to explicitly invalidate parent grid on Windows.

[Copilot]

Returning immediately after invalidating the parent skips the grid's own InvalidateMeasure call. To guarantee both the grid and its container are re‐measured, consider calling grid.InvalidateMeasure() before or after invalidating the parent instead of exiting early.

Suggested change

	return;
	grid.InvalidateMeasure();