private void BtnSave_Click(object sender, RoutedEventArgs e)
        {
            ReferenceBindViewModel m = (ReferenceBindViewModel)this.DataContext;

            System.Diagnostics.Debug.WriteLine($"Size = {m.Size}.");
            System.Diagnostics.Debug.WriteLine($"Deep.MyString = {m.Deep.MyString}.");
        }
        private void BtnRead_Click(object sender, RoutedEventArgs e)
        {
            ReferenceBindViewModel m = (ReferenceBindViewModel)this.DataContext;

            m.Amount     = 21;
            m.Size       = 30.3;
            m.ProductId  = Guid.NewGuid();
            m.TestDouble = 0.01;
            m.Deep       = new MyModel4()
            {
                MyString = "hello"
            };
        }
        public ReferenceBindWindow()
        {
            InitializeComponent();

            ReferenceBindViewModel rbvm = new ReferenceBindViewModel()
            {
                Size       = 90.11,
                Amount     = 51,
                ProductId  = Guid.NewGuid(),
                TestDouble = 90.33,
                Deep       = new MyModel4()
                {
                    MyString = "New Values."
                }
            };

            this.DataContext = rbvm;
        }