c#程序说答案是正确的，无论输入如何

Question

程序总是说你输入的任何数字都是正确的。当您键入字符时，它会输出不正确。我不确定它为什么这样做。我是 C# 新手，所以放轻松！

   // Create a Random object to generate random numbers.
    Random randomizer = new Random();

    // for the addition problem. 
    int num1;
    int num2;
    int sum;
    int correct;
    int incorrect;

    private void play_Load(object sender, EventArgs e)
    {
        StartTheGame();

    }

    public void StartTheGame()
    {
        num1 = randomizer.Next(11);
        num2 = randomizer.Next(11);
        sum = num1 + num2;
        labelNum1.Text = num1.ToString();
        labelNum2.Text = num2.ToString();
    }

    private void labelNum1_Click(object sender, EventArgs e)
    {

    }

    private void timer1_Tick(object sender, EventArgs e)
    {

    }

    private void btnSub_Click(object sender, EventArgs e)
    {
        if (int.TryParse(txtUserAnswer.Text, out sum))
        {
            MessageBox.Show("Correct Answer!", "Correct");
            correct++;
        }
        else
        {
            MessageBox.Show("You messed up.", "Incorrect");
            incorrect++;
        }
        txtUserAnswer.Clear();
        txtUserAnswer.Focus();
        StartTheGame();

        if(correct == 5)
        {
            MessageBox.Show("Congrats! You defeated the monster.", "Next Level");
        }

        if(incorrect == 3)
        {
            MessageBox.Show("You've been defeated. Nerd.", "Loser");
            Application.Exit();
        }
    }

请帮帮我！这是为了学校，这让我很困扰！

Answer 1

您在这里所做的只是尝试解析。只要int.TryParse(txtUserAnswer.Text, out sum)的输入是整数，这个条件总是true。

txtUserAnswer.Text = "1235"; //this result in true
txtUserAnswer.Text = "44"; //this result in true
txtUserAnswer.Text = "999999"; //this result in true
txtUserAnswer.Text = "123bbn"; //this result in false

您必须使用不同于sum 的变量名添加检查条件。否则，您的sum 将被用户的输入替换：

int guesssum; //declare this
.
.
if (int.TryParse(txtUserAnswer.Text, out guesssum)) //use guesssum here
{
    if (guesssum == sum){
        MessageBox.Show("Correct Answer!", "Correct");
        correct++;
    }
    else {
         //wrong, do something!
    }
}