mscorlib.dll中发生了未处理的“System.FormatException”类型异常

Question

每次我点击计算按钮时，我都会收到以下消息： mscorlib.dll中出现未处理的“System.FormatException”类型的异常附加信息：输入字符串的格式不正确。

当工资输入低于9.75美元时，我应该显示一条消息。

然后它突出显示这行代码：

if (Convert.ToInt32(RateTextBox.Text) < 9.75m)

这是Calculate Button方法（我确定我犯了多个错误）：

 private void CalcButton_Click(object sender, EventArgs e)
    {  // The “Calculate” button calculates gross pay, taxes, and net pay and then      displays name, department, gross pay, taxes, and net pay using currency format for various amounts in the rich text box
        // Gross pay=  (hours * rate)
        // Taxes= (25% of gross pay)
        // Net pay (gross pay ?taxes)



        //calculate         


        Gross_pay = Convert.ToInt32(HoursTextBox.Text) * decimal.Parse(RateTextBox.Text);
        Taxes = TAX * Gross_pay;
        Net_Pay = Gross_pay - Taxes;

        annual_salary = Net_Pay;



        //display
        DisplayOutPut.Text = "";
        DisplayOutPut.Text += NameTextBox.Text + "\n";
        DisplayOutPut.Text += "Hours:" + HoursTextBox.Text + "\n";
        DisplayOutPut.Text += "Rate:" + RateTextBox.Text + "\n";
        DisplayOutPut.Text += "Gross Pay:" + Gross_pay.ToString("C") + "\n"; // Hours*Rate
        DisplayOutPut.Text += "Taxes:" + Taxes.ToString("C") + "\n";
        DisplayOutPut.Text += "Net Pay:" + Net_Pay.ToString("C");

        //handling the invalid inputs
        if (NameTextBox.Text == "")
        { MessageBox.Show("Name is missing.", "Error"); }

        if (Convert.ToInt32(HoursTextBox.Text) >= 70)
        { MessageBox.Show("Please Enter a Valid hour.", "Invalid data type."); }

        if (RateTextBox.Text == "" && (RateTextBox.Text == ","))
        { MessageBox.Show("Please Enter a valid amount.", "Invalid data type ($)"); }

        if (Convert.ToInt32(HoursTextBox.Text) >= 70)
        { MessageBox.Show("You have exceeded the maximum hours per week."); }

        else if (Convert.ToInt32(HoursTextBox.Text) < 10)
        { MessageBox.Show("You cannot input less than 10 hours."); }

        if (Convert.ToInt32(RateTextBox.Text) < 9.75m)
        { MessageBox.Show("Please enter the minimum wage."); }


        //overtime pay
        if (Convert.ToInt32(HoursTextBox.Text) >= 41)
        {
            Gross_pay = Convert.ToInt32(HoursTextBox.Text) * decimal.Parse(RateTextBox.Text) * 1.5m;
            DisplayOutPut.Text += "Gross Pay:" + Gross_pay.ToString("C") + "\n";
        }

        //Medical/Dental and 401k deductions...as well as tax collected.
        if (MedicalDentalDeductions.Checked)
        {
            Gross_pay = Convert.ToInt32(HoursTextBox.Text) * decimal.Parse(RateTextBox.Text) - 50.00m;
        }

    if(FourOneKDeduction.Checked)
    {
        Gross_pay = Convert.ToInt32(HoursTextBox.Text) * decimal.Parse(RateTextBox.Text) - 0.05m * 100;


    }


    if ((MedicalDentalDeductions.Checked) && (FourOneKDeduction.Checked))
    { Taxes = TAX * Gross_pay; }
      DisplayOutPut.Text= "Medical/Dental deduction:" + Taxes +"401k deduction:"+ Taxes;

    }

Answer 1

您正在将数字转换为整数 。 所以，如果你输入（比如说）9.5会失败，因为它不是一个整数。

您几乎肯定会使用decimal.TryParse ，注意返回值将说明解析是否成功。

decimal userRate;
if (!decimal.TryParse(RateTextBox.Text, out userRate))
{
    // Indicate to the user that the input is invalid, and return from
    // the method
}
// Now use userRate

Answer 2

如果输入的内容不能转换为整数 ，则会出现错误，因为您使用的是Convert.ToInt32 。 尝试：

if (Convert.ToDecimal(RateTextBox.Text) < 9.75m)

或者，更好的是，切换到使用decimal.TryParse ，这将允许您轻松处理不正确的输入而无需异常处理。