private void navigationHelper_SaveState(object sender, SaveStateEventArgs e)
 {
     SaveState(sender, e);
 }
 /// <summary>
 /// Override this method to save your state
 /// </summary>
 /// <param name="sender"></param>
 /// <param name="e"></param>
 protected virtual void SaveState(object sender, SaveStateEventArgs e)
 {
 }