Fix for Page OnAppearing triggered twice when navigating via ShellItem change with PresentationMode set to Modal

[SyedAbdulAzeemSF4852]

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!

Issue Details

• When navigating to a new ShellItem using a route like //SomeRoute/SomePage, and SomePage specifies Shell.PresentationMode="Modal", the page’s OnAppearing event is called twice.

Root Cause

• During Shell navigation between different ShellItems (e.g., //tab1 to //tab2/modal), modal pages receive duplicate lifecycle events because the old ShellSection calls SendDisappearing() on the modal page during its cleanup, but the modal page now belongs to the new ShellSection, which also manages its lifecycle events.

Description of Change

• Added an IsVisibleSection check in PresentedPageDisappearingmethod to ensure lifecycle events are only sent by the active ShellSection. This prevents duplicate events on modal pages during ShellItem transitions by blocking non-visible (previous) ShellSections from managing pages they no longer own.

Issues Fixed

Fixes #31584

Validated the behaviour in the following platforms

• Windows
• Android
• iOS
• Mac

Output

Platform	Before	After
iOS	iOS_Before.mov	iOS_After.mov
Android	Android_Before.mov	Android_After.mov

[dotnet-policy-service]

Hey there @@SyedAbdulAzeemSF4852! 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]

Pull Request Overview

This PR fixes an issue where OnAppearing is called twice on modal pages when navigating between different ShellItems in .NET MAUI Shell. The fix adds a check to prevent non-visible ShellSections from sending lifecycle events to pages they no longer own.

Key changes:

• Modified PresentedPageDisappearing() in ShellSection.cs to check IsVisibleSection before sending disappearing events to modal pages
• Added UI test case to verify the fix prevents duplicate OnAppearing calls during ShellItem transitions with modal pages

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
src/Controls/src/Core/Shell/ShellSection.cs	Added IsVisibleSection check in PresentedPageDisappearing() to prevent duplicate lifecycle events on modal pages during ShellItem transitions
src/Controls/tests/TestCases.HostApp/Issues/Issue31584.cs	Added HostApp test page demonstrating the bug and verifying the fix with modal navigation between ShellItems
src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue31584.cs	Added NUnit UI test to verify modal page OnAppearing is triggered only once during ShellItem navigation

[sheiksyedm]

/azp run

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Azure Pipelines successfully started running 3 pipeline(s).

[PureWeen]

/rebase

[PureWeen]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[PureWeen]

Can you rework this to just be a unit test vs a UItest?

I think we can validate this purely by being a UITest?

[PureWeen]

Conversation_Summary_PR_32582.md

@SyedAbdulAzeemSF4852 @sheiksyedm

I had copilot add unit tests based on your UITest

I asked it this

"The PR here #32582 is using a UITest can you instead make this a unit test? Please make sure to validate that the test fails without the changes and then it's fixed with the changes. Feel free to add any additional tests."

and then it generated these tests

Please review added tests and delete UITests if they look good

[SyedAbdulAzeemSF4852]

Conversation_Summary_PR_32582.md

@SyedAbdulAzeemSF4852 @sheiksyedm

I had copilot add unit tests based on your UITest

I asked it this

"The PR here #32582 is using a UITest can you instead make this a unit test? Please make sure to validate that the test fails without the changes and then it's fixed with the changes. Feel free to add any additional tests."

and then it generated these tests

Please review added tests and delete UITests if they look good

@PureWeen , I’ve gone through the tests Copilot added. Two of the tests seemed quite similar and were essentially testing the same thing, so I’ve removed one of them. I’ve also removed the original UI test since the remaining unit tests provide the necessary coverage.

[sheiksyedm]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[PureWeen]

/rebase

[PureWeen]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).