[iOS] Selected items are not highlighted in the UI during the initial loading when using MultiSelection in the CollectionView.

[LogishaSelvarajSF4525]

Description

In .NET MAUI, on the iOS platform, when the CollectionView is initialized with Items 1 and Items 2 pre-selected, the selection is applied in the model, but these items are not visually highlighted with a background color to indicate they are selected.

Note: Since this issue has not been reproduced in either the sandbox sample or the HostApp sample, the initial case is working properly. However, when dynamically clearing and adding selected items, the selection is not reflected in the UI on iOS.

While addressing this issue, please enable the test case: CollectionViewUITests.MultipleBoundSelection, and ensure that all scenarios work as expected.

In iOS,

Screen.Recording.2025-01-03.at.4.53.26.PM.mov

In android,

Screen.Recording.2025-01-03.at.4.26.44.PM.mov

Steps to Reproduce

1. Run the app on an iOS device or simulator.MultipleBoundsSample.zip
2. Ensure that the CollectionView is loaded on the screen with a list of items.
3. In the view model, the SelectedItems collection is populated with items 1 and 2.
4. The CollectionView is set to SelectionMode="Multiple", and Items 1 and Item2 are pre-selected programmatically.
5. Observe that the SelectedItems collection contains the correct items (Item 1 and Item 2).
6. However, visually, the background color of the pre-selected items (items 1 and 2) does not change to indicate selection, and there is no visual highlight, even though the items are marked as selected in the model.

Expected Behavior:
When Items 1 and Items 2 are pre-selected in the CollectionView, they should appear visually highlighted, with their background color changed to indicate their selected state.

Actual Behavior:
Items 1 and Items 2 are pre-selected, but they do not visually appear highlighted with a background color.

Link to public reproduction project repository

No response

Version with bug

9.0.21 SR2.1

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

9.0.21 SR2.1

Affected platforms

iOS

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

[similar-issues-ai]

We've found some similar issues:

• Initially selected item in CollectionView isn't highlighted on iOS #14730 , similarity score: 85%
• Custom selection styles for items in CollectionView are ignored when programmatically selecting an item #18933 , similarity score: 82%
• [Mac] Unable to Select Multiple Items in CollectionView with SelectionMode='Multiple' #26942 , similarity score: 82%
• [MAUI] I4_ Selection - Selected items are not highlighted #23296 , similarity score: 82%
• CollectionView SelectedItem not highlighted on Android until scroll #5117 , similarity score: 81%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[karthikraja-arumugam]

It looks similar to this #8435

[mattleibow]

As OP points out, we have a test but it was disabled:

maui/src/Controls/tests/TestCases.Shared.Tests/Tests/CollectionView/CollectionViewUITests.MultipleBoundSelection.cs

Line 17 in 46096ff

[FailsOnAllPlatformsWhenRunningOnXamarinUITest("Click does not find CollectionView elements.")]

[mattleibow]

It is likely related to or a duplicate of #15718