public static ScreenManager getInstance()
 {
     if (singleton == null)
         singleton = new ScreenManager();
     return singleton;
 }
        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here

            //Microsoft.Phone.Controls.

               screenManager = ScreenManager.getInstance();

            //String toto = Content.Load<String>("0.txt");

            base.Initialize();
        }