private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (timerRunning == false)
            {
                timer.Start();
                timerRunning = true;
            }
            if (gameEnd == true)
            {
                return;
            }

            bool lost = false;
            int  b_n  = Convert.ToInt32((sender as Button).Name.Replace("B", ""));

            if (flagged[game.GetRowFromPos(b_n), game.GetColFromPos(b_n)] == true)
            {
                return;
            }
            else
            {
                lost = game.OpenCell(b_n);
            }

            UpdateWindow();

            if (lost == false)
            {
                timer.Stop();
                gameEnd = true;
            }
            else if (game.Finished() == true)
            {
                timer.Stop();
                gameEnd = true;
            }
        }