How do I implement a ViewModel in Xamarin.Forms?

How do I implement a ViewModel in Xamarin.Forms?

To implement a ViewModel in Xamarin.Forms, you typically create a class that implements the INotifyPropertyChanged interface.

What is the purpose of the INotifyPropertyChanged interface?

The INotifyPropertyChanged interface notifies the view when a property value changes, allowing for automatic UI updates.

Can you show me a simple example of a ViewModel?

Sure! Here's a basic example:

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

    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

How do I bind this ViewModel to my XAML page?

You can bind the ViewModel to your XAML page by setting the BindingContext property in the code-behind or directly in XAML.