CollectionView Faults With InvalidOperationException on Windows

[david-maw]

Description

In trying to write a repro for a bug I created a simple CollectionView app. It works fine on Android but on Windows selecting an item by way of setting a property bound to CollectionView.SelectedItem (with Mode=TwoWay) faults with an InvalidOperationException with the message "Unexpected type for enumerator".

Steps to Reproduce

Clone the repository, build and run the app on Windows, you should see:

Click on the "Select First Item" button and it will fault.

In contrast, if you build and run it on Android and click on the "Select First Item" button it will simply select the first item.

Alternatively, if you first click on of the buttons labelled 'Button' the app will catch and ignore the exception, but the item will not be selected although the property will be updated. The values of the SelectedPerson Property and of CollectionView.SelectedItem are both displayed by the app. It's not clear to me whether this is the same problem or a different one, so I didn't raise a separate incident.

One other observation. If you run the app on Android you'll see this:

Note that OnCollectionViewScrolled has been called, allowing the app to see initial values. This initial call is helpful and does not happen on Windows.

Link to public reproduction project repository

https://github.com/david-maw/SimpleCollectionView-Exception.git

Version with bug

9.0.10 SR1

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows 11

Did you find any workaround?

No response

Relevant log output