private void btnAtras_Click(object sender, RoutedEventArgs e)
        {
            LOGIN LG = new LOGIN();

            LG.Show();
            this.Close();
        }
 private void BtnCerrar_Click(object sender, RoutedEventArgs e)
 {
     if (MessageBox.Show("¿Seguro que desea salir?", "Mensaje", MessageBoxButton.YesNo, MessageBoxImage.Question) == MessageBoxResult.Yes)
     {
         LOGIN LG = new LOGIN();
         LG.Show();
         this.Close();
     }
 }