带小数分隔符的数字错误地转换为Double

Question

在使用文化信息时,将数字转换为double时,我遇到了奇怪的行为.使用荷兰文化进行
转换时"3,3",处理正确.如果我"3,3"使用美国文化转换,它会返回33.我期待一个错误.看我的例子:

static void Main(string[] args)
{
    CultureInfo cultureDutch = new CultureInfo("nl-NL");
    CultureInfo cultureUS = new CultureInfo("en-US");

    System.Threading.Thread.CurrentThread.CurrentCulture = cultureDutch;
    Console.WriteLine("Input 3,3 --> Expected 3,3");
    Console.WriteLine("Output = " + Convert.ToDouble("3,3", cultureDutch));
    // Actual result --> 3,3

    Console.WriteLine("Input 3,3 --> Expected InvalidCastException");
    Console.WriteLine("Output = " + Convert.ToDouble("3,3", cultureUS));
    // Actual result --> 33

    Console.WriteLine();
    Console.WriteLine();

    System.Threading.Thread.CurrentThread.CurrentCulture = cultureUS;
    Console.WriteLine("Input 3.3 --> Expected InvalidCastException");
    Console.WriteLine("Output = " + Convert.ToDouble("3.3", cultureDutch));
    // Actual result --> 33

    Console.WriteLine("Input 3.3 --> Expected 3.3");
    Console.WriteLine("Output = " + Convert.ToDouble("3.3", cultureUS));
    // Actual result --> 3.3
    Console.ReadLine();
}

处理这个问题的正确方法是什么？当小数(或千位)分隔符无效时,我更喜欢异常.

Answer 1

结合 Boas Enkler 的回答，我已经能够解决这个问题。因此，首先我将根据当前文化扫描输入中的千位分隔符。最后，我将把输入值解析为双精度值。

private static string RemoveThousandSeparator(string input)
    {
        Regex removeThousandSeparatorExpr = new Regex(@"^-?(?:\d+|\d{1,3}(?:\"
                        + <CultureInfo>.NumberGroupSeparator + @"\d{3})+)(?:\"
                        + <CultureInfo>.NumberDecimalSeparator + @"\d+)?$");
        Match match = removeThousandSeparatorExpr.Match(input);
        if (match.Success)
        {
            input = input.Replace(<CultureInfo>.NumberGroupSeparator, "");
        }
        else
        {
            throw new Exception("Invalid input value");
        }

        return input;
    }