What is MVVM and how does it help?

Model-View-View Model (MVVM) is a software architectural pattern that was famously introduced by John Gossman on his blog back in 2005 and is now commonly used when developing WPF applications. Its main purpose is to provide a Separation of Concerns between the business model, the User Interface (UI), and the business logic. It does this by dividing them into three distinct types of core components: Models, Views, and View Models. Let's take a look at how they are arranged and what each of these components represent:

As we can see here, the View Models component sits between the Models and the Views and provides two-way access to each of them. It should be noted at this point that there should be no direct relationship between the Views and Models components and only loose connections between the other components. Let's now take a closer look at what each of these components represent.