Model-View-ViewModel (MVVM)

The Model-View-ViewModel (MVVM) pattern is a software architectural pattern that separates the graphical user interface (the view) from the data (the model) and the logic that manipulates the data (the view model).

The MVVM pattern is derived from the Model-View-Controller (MVC) pattern, and shares many of the same goals. The two patterns are often used together, and the ViewModel is sometimes referred to as the "Model View" or the "MVC Model".

The main difference between the two patterns is that MVVM separates the view from the view model, whereas MVC combines the two. This separation allows for a more modular design, and it also makes it easier to unit test the view model logic.

The MVVM pattern is often used in conjunction with data binding, which is a way of automatically synchronizing the view and the view model. When data binding is used, the view model does not need to be explicitly updated; the changes will be automatically propagated to the view.

The MVVM pattern is well suited for use with declarative programming languages such as XAML, which is often used for creating user interfaces.

How can you explain view and ViewModel in MVVM?

View and ViewModel in MVVM

The Model-View-ViewModel (MVVM) is an architectural pattern used in software engineering that separates the graphical user interface (the view) from the data (the model) and the behavior (the view model).

The view model is a representation of the data that is used by the view. It is responsible for exposing the data to the view and for handling the user input. The view model also contains the logic that is used to manipulate the data.

The model is the data that is used by the view model. It can be a database, a web service, or anything else that contains the data that is needed by the view model.

The view is the graphical user interface that is used to display the data from the view model. What goes into the model in MVVM? The model in an MVVM application contains the data and business logic. The view contains the user interface. The view model contains the view's data binding and logic.

How do I create a ViewModel in MVVM?

There are a few different ways to create a ViewModel in MVVM. One way is to simply create a new class that inherits from the ViewModelBase class. Another way is to create a new class and implement the INotifyPropertyChanged interface.

The ViewModelBase class provides a basic implementation of the INotifyPropertyChanged interface and also exposes a few useful properties and methods for ViewModel development. The INotifyPropertyChanged interface is used to notify the view that a property on the ViewModel has changed and that the view should update itself accordingly.

When creating a ViewModel, it is often useful to think about what data the ViewModel will need to expose to the view, and what methods and properties will be needed in order to manipulate that data. For example, if the ViewModel is going to be used to display a list of items, it will need to expose a property that contains the list of items, and it will need methods for adding and removing items from the list.

It is also important to think about how the ViewModel will be used in conjunction with the view. For example, if the ViewModel is going to be used to display a list of items in a ListView control, it will need to implement the IList interface so that the ListView control can bind to it.

Once you have a good understanding of what the ViewModel will need to do, you can start creating it. As mentioned

Why MVVM is better than MVC?

MVVM is a more modern and flexible approach to application development than MVC. It enables developers to better separate concerns within their code and results in more maintainable and testable applications.

MVC can be seen as a more rigid and traditional approach to application development. It can be more difficult to unit test and maintain MVC applications due to the tight coupling between the controller and the view.