In which architectural pattern is a ViewModel used to expose data and commands to the View, enabling data binding?

In which architectural pattern is a ViewModel used to expose data and commands to the View, enabling data binding?

• A. Model-View-Controller
• B. Model-View-Presenter
• C. Model-View-Logic-Model
• D. Model-View-ViewModel

Answer: (D)

MVVM separates UI from logic by introducing a ViewModel that presents data and actions to the View. The View binds to properties and commands on the ViewModel, so the UI updates automatically when data changes and user actions trigger methods on the ViewModel. This two-way data binding and command binding is the hallmark of MVVM, enabling a clean separation between presentation and logic and making UI code more testable. The other patterns structure responsibilities differently—Controllers in MVC coordinate between view and model, and Presenters in MVP drive a view interface—without the same declarative binding between the View and a bindable data/command model.

MVVM separates UI from logic by introducing a ViewModel that presents data and actions to the View. The View binds to properties and commands on the ViewModel, so the UI updates automatically when data changes and user actions trigger methods on the ViewModel. This two-way data binding and command binding is the hallmark of MVVM, enabling a clean separation between presentation and logic and making UI code more testable. The other patterns structure responsibilities differently—Controllers in MVC coordinate between view and model, and Presenters in MVP drive a view interface—without the same declarative binding between the View and a bindable data/command model.