private void SetMailButtonIcon(System.ComponentModel.PropertyChangedEventArgs args)
{
if (args == null || args.PropertyName == "HasMail")
{
if (ServiceLocator.Current.GetInstance<MessagesViewModel>().HasMail)
appBarButtons[(int)ButtonEnum.Mail].IconUri = new Uri("\\Assets\\Icons\\read.png", UriKind.Relative);
else
appBarButtons[(int)ButtonEnum.Mail].IconUri = new Uri("\\Assets\\Icons\\email.png", UriKind.Relative);
}
}