Mastering the MVVM Design Pattern
The primary purpose of Model-View-ViewModel (MVVM) is to separate the UI code (view) from the data and business logic (model). This separation is achieved through the view model class, which acts as an intermediary between the view and the model.
Figure 2.1 – MVVM architecture
The MVVM pattern offers several key benefits:
- Reusability: The business logic can be reused across different modules or applications since it is independent of the current view.
- Testability: In an MVVM application, you can easily isolate and test the view, model, or view model without their dependencies.
- Clean code base and structure: The project becomes easier to understand when UI code is confined to views, business logic and data structures are in models, and view models act as connectors between them.
- Adaptation: The view model allows you to adapt your model to the UI without altering the data structure and business logic.
- Scalability: The aforementioned advantages contribute to better scalability. As your project grows, MVVM helps maintain organized and manageable code.
Although MVVM has been used across multiple platforms for many years, its concepts are sometimes misunderstood, leading to complex and hard-to-maintain code. This chapter includes recipes for following MVVM best practices, helping you achieve a clean architecture with minimal effort.
In this chapter, we’ll be covering the following recipes:
- Decoupling the UI from the view model
- Implementing auto-generated view models
- Implementing asynchronous commands
- Initializing bound collections without freezing the UI
- Interacting with the UI from the view model without breaking MVVM
- Sending messages between view models via different channels
- Injecting an application service into a view model using dependency injection
- Troubleshooting binding errors
