Here's a quick step-by-step tutorial on how to model a 3 level cascading dropdown combobox.
- HR Schema
- ReadOnly viewObject for Countries, Locations and Departments
You'll need to set viewCriterias on:
- Location filtered by CountryId
- Department filtered by LocationId
Create a viewObject that will utilize these models.
Add an lovModel for CountryId, LocationId and DepartmentId.
Test your ApplicationModule
And everything in the UI is just a matter of drag-and-drop and setting autosubmit on the selectOneChoice and partialTrigger on those component that has dependencies.