private void answer_operation(object sender, RoutedEventArgs e) { String inListContent; //写入列表框的内容 String content = answerBox.Text; //获取用户输入内容 if (content.Length == 0) //检测用户输入是否为空 { MessageBox.Show(mainWindow, "答案不能为空"); answerBox.Focus(); } else { int userAnswer = Int32.Parse(content); if (arithmetic.CheckAnswer(userAnswer)) { inListContent = arithmetic.strFormula + " = " + userAnswer.ToString() + " 正确"; answerList.Items.Insert(0, inListContent); //总做题数和正确题数计数 arithmetic.rightCount++; arithmetic.sumCount++; answerBox.Text = ""; answerBox.Focus(); } else { inListContent = arithmetic.strFormula + " = " + userAnswer.ToString() + " 错误\t" + "正确答案:" + arithmetic.formula[3].ToString(); answerList.Items.Insert(0, inListContent); //总做题数计数 arithmetic.sumCount++; answerBox.Text = ""; answerBox.Focus(); } set_question(sender, e);//重新设置题目 } }