CollectionView does not update when changing ItemsLayout

[mattleibow]

Description

I have a CollectionView with several items and I want to make a 2 column layout on wide screens and a 1 column layout on tall screens.

I tried setting a GridItemsLayout and changing the Span, but that did not work and then I tried changing the entire ItemsLayout, but still no updates in the app.

Restarting the app works, so this is just the result of changing at runtime.

Steps to Reproduce

Add a CollectionView with items, and then say write this code to toggle the layout on page size changes:

private void OnSizeChanged(object? sender, EventArgs e) =>
    collectionView.ItemsLayout = Width > 600
        ? new GridItemsLayout(2, ItemsLayoutOrientation.Vertical)
        : new LinearItemsLayout(ItemsLayoutOrientation.Vertical);

NOTE: this should all be doable with AdaptiveTriggers, but that is not working currently #7242

Version with bug

6.0 (current)

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

All

Did you find any workaround?

No response

Relevant log output

No response

[StepKie]

The same is true for ListView, btw.
When calling OnPropertyChanged(nameof(OverallRecords) (no matter if it is an ObservableCollection, ObservableRangeCollection or a basic List), the content of the collection view only updates when the area is manually scrolled.

After calling OnPropertyChanged(nameof(OverallRecords), in the following case

• FirstRecord updates correctly, with ViewModel code:
  public string FirstRecord => OverallRecords.FirstOrDefault()?.Record.Team.Name ?? "NONE";

• The CollectionView only updates after click/scroll ...

     <Label Text="{Binding FirstRecord}" />
     <ListView ItemsSource="{Binding OverallRecords}">
       <ListView.ItemTemplate>
         <DataTemplate>
           <ViewCell>
             <Label Text="{Binding Record.Team.Name}" />
           </ViewCell>
         </DataTemplate>
       </ListView.ItemTemplate>
     </ListView>

This cost me a good five hours to debug, and then I find this existing issue.
Incredible for a GA version of MAUI, really ... :(

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[ToolmakerSteve]

FWIW: I haven't looked at what Collection/ListView issues have been closed in the past two months, but initially there were MANY issues that came down to "Collection/ListView does not correctly update its layout when it should".

This sounds like yet another one.

Interestingly, programmatically forcing a layout does NOT (or at least didn't at the time) fix any of those. I infer that certain information is cached when the view is first built, and not correctly re-calculated in later layout cycles.