[iOS] Fixed the TargetInvocationException Occurs When Selecting Header/Footer After Changing ItemsLayout in CV2

[Ahamed-Ali]

Root Cause of the issue

• The SupplementaryView was not properly registered, leading to an exception during the call to DequeueReusableSupplementaryView when adding a header or footer after changing the ItemsLayout in CollectionView.

Description of Change

• Properly register both vertical and horizontal SupplementaryView types to prevent exceptions during dynamic layout changes.

Reference

• https://github.com/dotnet/maui/blob/main/src/Controls/src/Core/Handlers/Items/iOS/GroupableItemsViewController.cs#L61

Issues Fixed

Fixes #28678

Tested the behaviour in the following platforms

• Android
• Windows
• iOS
• Mac

Screenshot

Before Issue Fix	After Issue Fix
CrashOccured.mov	FixedCrash.mov

[dotnet-policy-service]

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

[Copilot]

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

Comments suppressed due to low confidence (2)

src/Controls/src/Core/Handlers/Items2/iOS/StructuredItemsViewController2.cs:76

• Both horizontal and vertical supplementary views are always registered regardless of layout orientation. Please add a clarifying comment to explain this behavior for maintainers and ensure that the public docs in the /docs/ folder reflect this change.

private protected virtual void RegisterSupplementaryViews(UICollectionElementKindSection kind)

src/Controls/src/Core/Handlers/Items2/iOS/GroupableItemsViewController2.cs:61

• As with StructuredItemsViewController2, the conditional check on layout orientation has been removed to register both horizontal and vertical supplementary views. Please document this change in both the code and associated public documentation.

private protected override void RegisterSupplementaryViews(UICollectionElementKindSection kind)