[Bug] CollectionView KeepLastItemInView ignored on initial load and reset

[hartez]

Description

A CollectionView with ItemsUpdatingScrollMode="KeepLastItemInView" will scroll to the last item as items are added individually, but on initial load or reset of the ObservableCollection, the CollectionView does not scroll the last item into view.

(This has been ported from #13231 so it can be tracked and addressed individually.)

Steps to Reproduce

1. Download the repro project and update to 5.0.0.1931 (or later)
2. Run the app.

Expected Behavior

Once the app has loaded the CollectionView items, the CollectionView will be scrolled (instantly, not animated) to display the last item.

CollectionView is scrolled to make the last item visible.

Actual Behavior

CollectionView scroll remains at the top.

Basic Information

• Version with issue: 5.0.0
• Last known good version: none
• Platform Target Frameworks:
  • iOS: all versions
  • Android: (haven't tested this yet, but probably)
  • UWP: Separate issue [Bug] CollectionView ItemsUpdatingScrollMode=KeepLastItemInView not working on UWP #9127
• Android Support Library / AndroidX Version:
• NuGet Packages:
• Affected Devices:

Reproduction Link

The repro project can be found in issue 13231. Update the issue to the latest stable (5.0.0.1931) and run it.

Workaround

[hartez]

Issue #13547 is related.

[Tommigun1980]

Hi Hartez and and thanks for looking into this! Yeah #13547 details this exact problem, along with a very finicky “workaround”. It also details some other issues related to this.

[Tommigun1980]

This is so hard to work around, as it’s very very hard to scroll a collection view to the bottom as it loads.
Any chance ghis could get fixed?

Thanks.