protected override void CreateConstraints()
        {
            base.CreateConstraints();

            ContentView.AddConstraints(

                _stackView.AtLeftOf(ContentView, PADDING),
                _stackView.AtTopOf(ContentView, PADDING),
                _stackView.AtRightOf(ContentView, PADDING),
                _stackView.AtBottomOf(ContentView, PADDING)
                );
        }