Universal App behavior ... press enter to move focus to desired control

CommandOnEnterPressFocus.cs

 /// <summary>
    /// <Interactivity:Interaction.Behaviors>
    /// <MoreBehaviors:CommandOnEnterPressFocus Target="{Binding ElementName=yourothercontrol}"  />
    /// </Interactivity:Interaction.Behaviors>
    /// </summary>
    [Microsoft.Xaml.Interactivity.TypeConstraint(typeof(TextBox))]
    class CommandOnEnterPressFocus : DependencyObject, IBehavior
    {

        public Windows.UI.Xaml.DependencyObject AssociatedObject { get; set; }


        public static readonly DependencyProperty TargetProperty = DependencyProperty.Register("Target", typeof(Control), typeof(CommandOnEnterPressFocus), new PropertyMetadata(null));

        /// <summary>
        /// The focus target.
        /// </summary>
        public Control Target
        {
            get { return (Control)base.GetValue(TargetProperty); }
            set { base.SetValue(TargetProperty, value); }
        }


        public void Attach(Windows.UI.Xaml.DependencyObject associatedObject)
        {
            this.AssociatedObject = associatedObject;
            var textbox = this.AssociatedObject as TextBox;
            textbox.KeyDown += textbox_KeyDown;
        }

        public void Detach()
        {
            var textbox = this.AssociatedObject as TextBox;
            textbox.KeyDown -= textbox_KeyDown;
        }

        void textbox_KeyDown(object sender, Windows.UI.Xaml.Input.KeyRoutedEventArgs e)
        {
            if (e.Key == Windows.System.VirtualKey.Enter)
            {
               
                if (Target != null)
                {
                    Target.Focus(FocusState.Programmatic);
                }

            }

        }
    }