MVVM in WPF - How to alert ViewModel of changes in Model… or should I?

Question

I am going through some MVVM articles, primarily this and this.

My specific question is: How do I communicate Model changes from the Model to the ViewModel?<

Answer 1

There's nothing wrong to implement INotifyPropertyChanged inside Model and listen to it inside ViewModel. In fact you can even dot into model's property right in XAML : {Binding Model.ModelProperty}

As for dependent / calculated read-only properties, by far I haven't seen anything better and simpler than this: https://github.com/StephenCleary/CalculatedProperties. It's very simple but incredibly useful, it's really "Excel formulas for MVVM" - just works same way as Excel propagating changes to formula cells without extra effort from your side.