附加导师程序无法正常工作***阅读说明***

下面是一个名为“加法导师”的程序的代码。该程序生成2个随机数,并要求用户回答这两个随机数的加法。问题是,每次我正确回答问题时,messagebox都会返回else操作(“不正确”)。我的程序有什么问题?请保持答案简单,我的编程知识和术语非常有限。非常感谢您的帮助!

namespace Addition_Tutor
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            //Create a random object.
            Random rand = new Random();
            {
                //Declare an Integer
                int number1;

                //Generate a random integer and assign it to number1
                number1 = rand.Next(400) + 100;

                //Send random number to numberlabel1
                numberLabel1.Text = Convert.ToString(number1);
            }
            {
                //Declare an Int Variable
                int number2;

                //Generate a random integer and assign it to number2
                number2 = rand.Next(400) + 100;

                //Send random number to numberlabel2
                numberLabel2.Text = Convert.ToString(number2);
            }
        }

        private void checkButton_Click(object sender, EventArgs e)
        {

                //declare an Int Variable for Correct Answer
                int correctAnswer;
                correctAnswer = Convert.ToInt32("" + numberLabel1.Text + numberLabel2.Text);

            //check to see if the userAnswer and correctAnswer match.
            int userAnswer;
            userAnswer = Convert.ToInt32(answerTextBox.Text);

            if (userAnswer == correctAnswer)
            {
                MessageBox.Show("Your Answer is Correct");
            }
            else
            {
                MessageBox.Show("Your Answer is Incorrect");
            }
        }
        private void clearButton_Click(object sender, EventArgs e)
        {
            //clear the labels and textboxes.
            numberLabel1.Text = "";
            numberLabel2.Text = "";
            answerTextBox.Text = "";
        }

        private void exitButton_Click(object sender, EventArgs e)
        {
            //close the form
            this.Close();
        }
    }
}