MVVM in Delphi: Architecting and Building Model View ViewModel Applications

© John Kouraklis 2016

John Kouraklis, MVVM in Delphi, 10.1007/978-1-4842-2214-0_4

4. Two-Way Communication

John Kouraklis¹ 

(1)London, UK

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. Then consider Figure 3-4 and the way the initial labels captions are retrieved. Based on this figure and the description of the layout of the MVVM model as presented in Chapter 1, we may notice that each one of the components communicate with the next in the layout in an one-way arrangement, as awareness of each element is limited. The View is aware of the ViewModel, but the ViewModel doesn’t know anything about the View. Likewise, ...