Two-Way Communication
John Kouraklis · Apress eBooks · 2016
Take a moment to revisit the code developed for POSApp so far. In particular, try to identify the way that communication is being delivered among the View, the ViewModel, and the Model. The View is aware of the ViewModel, but the ViewModel doesn’t know anything about the View. Likewise, the ViewModel is aware of the Model, but not vice versa. This design has served you well in POSApp up to this point, as you simply wanted to get the values of the labels.