Chapter 5, Advanced Controls

1. ActivityIndicator shows that something is happening, while ProgressBar tells the user what fraction of the task is complete.
2. The essential difference as far as we are concerned is that events are typically handled in the code-behind, while commands are handled in ViewModel. Handling commands in ViewModel is preferable because it makes creating unit tests easier or possible.
3. WeakReferenceManager is the primary object used in messaging, allowing ViewModel to send notifications to View or another ViewModel without a reference to that object, thus supporting loose coupling.
4. Styles allow you to create a uniform appearance across instances of controls, centralizing the properties and providing all the advantages of well-factored code.
5. One way to refactor styles is to create a base style and then use BasedOn to create derived types, adding or overriding properties as needed.