What structure and components does the MVVM pattern include?

The MVVM (Model-View-ViewModel) pattern divides an application into three main components:

• Model — represents data and business logic. This layer works with data, such as database models or services.
• View — responsible for displaying data to the user. These are UI components that show information and accept user input.
• ViewModel — acts as an intermediary between the Model and the View. It contains presentation logic, transforms data from the Model into a format suitable for the View, and handles user commands.

This separation improves testability, maintainability, and reusability of code. The View and ViewModel are usually linked through binding mechanisms, which reduces the amount of code needed to update the UI.

Example in C# using WPF:

public class PersonViewModel : INotifyPropertyChanged
{
    private string name;
    public string Name
    {
        get => name;
        set
        {
            name = value;
            OnPropertyChanged();
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string propName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
    }
}

Here, the ViewModel contains a property 'Name' that the View can bind to for display and editing.