Why does ItemsSource require IList to support INotifyCollectionChanged?

[DanTravison]

Perhaps this has been answered before but...

Why does binding to ListBox.ItemsSource require the bound collection to implement IList to enable INotifyCollectionChanged?

In other word, I would expect a type that implements IReadOnlyList, INotifyPropertyChanged, and INotifyCollectionChanged to be a valid ItemSource. Is there a path where ItemsSource needs to be writeable by the ItemsControl?

I see this same issue with Maui and ended up having to implement IList explicitly and throw NotSupportedException for all IList methods that update the list.

To phrase this as a feature request: ItemsSource should support read-only collections/lists that implement INotifyCollectionChanged.

[maxkatz6]

This was discussed in #8764

In short, it wasn't technically feasible until items source was refactored. Currently, it's just not implemented and untested scenario.