How to use IActivatableViewModel and ObservableCollections

[glen-nicol]

I imagine I am just naive coming from other frameworks. But I would like to limit a subscription to a service in a viewmodel that will modify a list of items to only when the viewmodel is loaded in the UI. So I figure I need to hook up IActivatableViewModel but when I do that the this.WhenActivated callback does not have the constructor function scope to set readonly ObservableCollection<> member variables that are backing ReadonlyObservableCollection<> properties bound to the ListBox.

So then the options seems to be

1. use a RW property of Ienumerable<> or similar to be able to set them asynchronously. I think I get warnings about just using a single collection and modifying the collection instead of replacing it.
2. Make the viewModel disposable and then pass the responsibility of disposing to the creator. Although this really isn't an option for a viewmodel that is also participating in Routing. Unless I am unaware of a good way to hook into that system's transitions? Also this means the viewmodel needs to be recreated in order to show it again (for navigating back to the page)

EDIT: replaced OAPH with RW property when I remembered OAPH has constructor limitation too.

PS: kinda unrelated but is there a better way to do reactiveUI bindings for items in an Itemssource besides IViewFor<>? Creating ReactiveUserControls for list items with a couple properties is verbose/painful. I am aware I can still just put a datatemplate in the ItemTemplate property but then I lose strongly typed bindings.