Exposing opacity in a custom control in Silverlight

I built a custom control, TextBoxWithButton which is composed of a TextBox and a Button near it. I want to have an Opacity property in TextBoxWithButton, that when I change it, the opacity of both TextBox and Button changes.

This is the Opacity property in TextBoxWithButton :

        private double opacity = 100;
        public double Opacity
        {
            get { return opacity; }
            set
            {
                opacity = value;
                textBox.Opacity = opacity;
                button.Opacity = opacity;
            }                                       
        }

But how can I make the Opacity property in TextBoxWithButton a dependency property, so I can animate it开发者_Go百科, for example.

I think you should already have Opacity property inherited in your custom control form UIElement class. It will do exactly what you are asking for.