C# mscorlib.dll 中发生类型为“System.FormatException”的未处理异常
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An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll
提问by Syntax_Error
Every time I hit the calculate button I receive the following message: An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll Additional information: Input string was not in a correct format.
每次点击计算按钮时，我都会收到以下消息：mscorlib.dll 中发生类型为“System.FormatException”的未处理异常 附加信息：输入字符串的格式不正确。
I'm supposed to display a message when the wage input is below $9.75.
当工资输入低于 9.75 美元时，我应该显示一条消息。
It then highlights this line of code:
然后突出显示这行代码：
if (Convert.ToInt32(RateTextBox.Text) < 9.75m)
Here is the Calculate Button method (I'm sure I've made more than one error):
这是计算按钮方法（我确定我犯了不止一个错误）：
private void CalcButton_Click(object sender, EventArgs e)
{ // The “Calculate” button calculates gross pay, taxes, and net pay and then displays name, department, gross pay, taxes, and net pay using currency format for various amounts in the rich text box
// Gross pay= (hours * rate)
// Taxes= (25% of gross pay)
// Net pay (gross pay ?taxes)
//calculate
Gross_pay = Convert.ToInt32(HoursTextBox.Text) * decimal.Parse(RateTextBox.Text);
Taxes = TAX * Gross_pay;
Net_Pay = Gross_pay - Taxes;
annual_salary = Net_Pay;
//display
DisplayOutPut.Text = "";
DisplayOutPut.Text += NameTextBox.Text + "\n";
DisplayOutPut.Text += "Hours:" + HoursTextBox.Text + "\n";
DisplayOutPut.Text += "Rate:" + RateTextBox.Text + "\n";
DisplayOutPut.Text += "Gross Pay:" + Gross_pay.ToString("C") + "\n"; // Hours*Rate
DisplayOutPut.Text += "Taxes:" + Taxes.ToString("C") + "\n";
DisplayOutPut.Text += "Net Pay:" + Net_Pay.ToString("C");
//handling the invalid inputs
if (NameTextBox.Text == "")
{ MessageBox.Show("Name is missing.", "Error"); }
if (Convert.ToInt32(HoursTextBox.Text) >= 70)
{ MessageBox.Show("Please Enter a Valid hour.", "Invalid data type."); }
if (RateTextBox.Text == "" && (RateTextBox.Text == ","))
{ MessageBox.Show("Please Enter a valid amount.", "Invalid data type ($)"); }
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;
}
回答by Jon Skeet
You're converting a number to an integer. So if you entered (say) 9.5 that would fail, because it's not an integer.
您正在将数字转换为整数。因此，如果您输入（例如）9.5 会失败，因为它不是整数。
You should almost certainly be using decimal.TryParse, noting that the return value will say whether parsing succeeded or not.
您几乎肯定应该使用decimal.TryParse，请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
回答by Reed Copsey
You will get that error if you type something that's not convertible to an integer, since you used Convert.ToInt32. Try:
如果您键入的内容不能转换为 integer，则会出现该错误，因为您使用了Convert.ToInt32. 尝试：
if (Convert.ToDecimal(RateTextBox.Text) < 9.75m)
Or, better yet, switch to using decimal.TryParse, which will allow you to easily handle improper input without exception handling.
或者，更好的是，切换到 using decimal.TryParse，这将允许您轻松处理不正确的输入而无需异常处理。
