EventToCommand Xamarin Forms - BindableBehavior Source

eventtocommand-xamarin-forms-src-2.cs

public class BindableBehavior<T> : Behavior<T> where T : BindableObject
{
    public T AssociatedObject { get; private set; }

    protected override void OnAttachedTo(T visualElement)
    {
        base.OnAttachedTo(visualElement);

        AssociatedObject = visualElement;

        if (visualElement.BindingContext != null)
            BindingContext = visualElement.BindingContext;

        visualElement.BindingContextChanged += OnBindingContextChanged;
    }

    private void OnBindingContextChanged(object sender, EventArgs e)
    {
        OnBindingContextChanged();
    }

    protected override void OnDetachingFrom(T view)
    {
        view.BindingContextChanged -= OnBindingContextChanged;
    }

    protected override void OnBindingContextChanged()
    {
        base.OnBindingContextChanged();
        BindingContext = AssociatedObject.BindingContext;
    }
}