Question

我的老师为我提供了用于创建程序的代码，但是，当我运行它时，它给了我'FormatException未处理'。它建议我将字符串转换为DateTime，但这与代码无关。我真的无法确定问题所在。我正在使用C＃，通过Microsoft Visual Studio，如果有任何帮助的话。

private void btnAdd_Click(object sender, EventArgs e)
{
    student[] students = new student[5];
    int i;
    for (i = 0; i < 5; i++)
    {
        students[i] = new student();
        try
        {
            int counter = 0; //array index counter
            students[counter].personName = txtName.Text;
            students[counter].personGPA = Convert.ToDouble(txtGPA.Text);

            txtDisplay.Text += "Name: " + students[counter].Name + "\r\n GPA: " + students[counter].GPA.ToString();
            counter++; //increment the array index counter by 1
            txtName.Text = string.Empty;
            txtGPA.Text = string.Empty;
            txtName.Focus();
        } //end of code for the try block
        catch (ArgumentException) //GPA is out of range
        {
            MessageBox.Show("Please enter a proper GPA");
        }
        catch (IndexOutOfRangeException) //array is full
        {
            MessageBox.Show("There are already 5 students.");
        }
    }
}

class student
{
    public String personName;
    public Double personGPA;

    public string Name
    {
       // get;
        //set; 
        get { return personName; }
        set { personName = value; }
    }

    public double GPA
    {
        //get;
        //set;
        get {return personGPA; }
        set { personGPA = value; }
    }        
}

Answer 1

我们来看看：

 for (...) {
   ...
   students[counter].personGPA = Convert.ToDouble(txtGPA.Text);
   ...
   txtGPA.Text = string.Empty;

您解析 txtGPA.Text然后清除并尝试再次解析（因为代码在 for loop ）。 empty 值无法转换为double，您将抛出异常。

可能你想拉循环中的所有值：

 double gpa = Convert.ToDouble(txtGPA.Text); 
 txtGPA.Text = String.Empty;

 for (...) {
   ... 
   students[counter].personGPA = gpa;

请注意，students[counter]仍然是非常可疑的代码，因为counter不是循环变量（即i）。

格式异常未处理......？

1 个答案: