private void ButtonAnswer(object sender, EventArgs e) { Button btn = (Button)sender; String questionnumber = question.questionnumber; int answerID = Int32.Parse(btn.ClassId); if (btn.BackgroundColor == Color.LimeGreen) { controller.DeleteUserAnswer(answerID); btn.BackgroundColor = Color.Default; } else { controller.AddUserAnswer(questionnumber, answerID); btn.BackgroundColor = Color.LimeGreen; } }