I thought I should add a post with the full list of posts in the D-V-VM pattern. They are:

DataModel-View-ViewModel pattern: 1 (overview)

DataModel-View-ViewModel pattern: 2 (first implementation of DataModel class)

DM-V-VM part 3: A sample DataModel

DM-V-VM part 4: Unit testing the DataModel

DM-V-VM part 5: Commands

DM-V-VM part 6: Revisiting the data model

DM-V-VM part 7: Encapsulating commands

DM-V-VM part 8: View Models