What are View Models in Xamarin.Forms?

What are View Models in Xamarin.Forms?

View Models in Xamarin.Forms are classes that implement the MVVM (Model-View-ViewModel) pattern, helping to separate UI logic from business logic.

How do I implement a View Model in my Xamarin.Forms app?

To implement a View Model, create a class that inherits from INotifyPropertyChanged, define properties for your data, and bind them to your views.

Can you give me an example of a simple View Model?

Sure! Here's a simple View Model:

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

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

What is the purpose of INotifyPropertyChanged?

INotifyPropertyChanged is an interface that notifies clients, typically binding clients, that a property value has changed, allowing the UI to update automatically.