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This question is about two MAUI controls (Switch and ListView) - I'm asking about them both in the same question as I'm expecting the root cause of the problem to be the same for both controls. It's entirely possible that they're different problems that just share some common symptoms though. (CollectionView has similar issues, but other confounding factors that make it trickier to demonstrate.)

I'm using 2-way data binding in my MAUI app: changes to the data can either come directly from the user, or from a background polling task that checks whether the canonical data has been changed elsewhere. The problem I'm facing is that changes to the view model are not visually propagated to the Switch.IsToggled and ListView.SelectedItem properties, even though the controls do raise events showing that they've "noticed" the property changes. Other controls (e.g. Label and Checkbox) are visually updated, indicating that the view model notification is working fine and the UI itself is generally healthy.

Build environment: Visual Studio 2022 17.2.0 preview 2.1
App environment: Android, either emulator "Pixel 5 - API 30" or a real Pixel 6

The sample code is all below, but the fundamental question is whether this a bug somewhere in my code (do I need to "tell" the controls to update themselves for some reason?) or possibly a bug in MAUI (in which case I should presumably report it)?

The sample code below can be added directly a "File new project" MAUI app (with a name of "MauiPlayground" to use the same namespaces), or it's all available from my demo code repo. Each example is independent of the other - you can try just one. (Then update App.cs to set MainPage to the right example.)

Both examples have a very simple situation: a control with two-way binding to a view-model, and a button that updates the view-model property (to simulate "the data has been modified elsewhere" in the real app). In both cases, the control remains unchanged visually.

Note that I've specified {Binding ..., Mode=TwoWay} in both cases, even though that's the default for those properties, just to be super-clear that that isn't the problem.

The ViewModelBase code is shared by both examples, and is simply a convenient way of raising INotifyPropertyChanged.PropertyChanged without any extra dependencies:

ViewModelBase.cs: