Prism Tabbed Navigation

BehaviorBase{T}.cs

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

        protected override void OnAttachedTo( T bindable )
        {
            base.OnAttachedTo( bindable );
            AssociatedObject = bindable;

            if( bindable.BindingContext != null )
            {
                BindingContext = bindable.BindingContext;
            }

            bindable.BindingContextChanged += OnBindingContextChanged;
        }

        protected override void OnDetachingFrom( T bindable )
        {
            base.OnDetachingFrom( bindable );
            bindable.BindingContextChanged -= OnBindingContextChanged;
            AssociatedObject = null;
        }

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

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

IMultiPageNavigationAware.cs

    public interface IMultiPageNavigationAware
    {
        void OnInternalNavigatedFrom( NavigationParameters navParams );
        void OnInternalNavigatedTo( NavigationParameters navParams );
    }

MultiPageNavigationBehavior.cs

    public class MultiPageNavigationBehavior : BehaviorBase<MultiPage<Page>>
    {
        private Page _lastSelectedPage;

        protected override void OnAttachedTo( MultiPage<Page> bindable )
        {
            base.OnAttachedTo( bindable );
            bindable.CurrentPageChanged += CurrentPageChangedHandler;
        }

        protected override void OnDetachingFrom( MultiPage<Page> bindable )
        {
            base.OnDetachingFrom( bindable );
            bindable.CurrentPageChanged -= CurrentPageChangedHandler;
        }

        private void CurrentPageChangedHandler( object sender, EventArgs args )
        {
            NavigationParameters parameters = new NavigationParameters();

            var lastPageContextAware = _lastSelectedPage?.BindingContext as IMultiPageNavigationAware;
            lastPageContextAware?.OnInternalNavigatedFrom( parameters );
            
            var newPageContextAware = AssociatedObject.CurrentPage.BindingContext as IMultiPageNavigationAware;
            newPageContextAware?.OnInternalNavigatedTo( parameters );

            _lastSelectedPage = AssociatedObject.CurrentPage;
        }
    }