Switch语句贯穿是我个人喜欢Switch vs. if/else if结构的主要原因之一。下面是一个例子:

static string NumberToWords(int number)
{
    string[] numbers = new string[] 
        { "", "one", "two", "three", "four", "five", 
          "six", "seven", "eight", "nine" };
    string[] tens = new string[] 
        { "", "", "twenty", "thirty", "forty", "fifty", 
          "sixty", "seventy", "eighty", "ninety" };
    string[] teens = new string[]
        { "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen",
          "sixteen", "seventeen", "eighteen", "nineteen" };

    string ans = "";
    switch (number.ToString().Length)
    {
        case 3:
            ans += string.Format("{0} hundred and ", numbers[number / 100]);
        case 2:
            int t = (number / 10) % 10;
            if (t == 1)
            {
                ans += teens[number % 10];
                break;
            }
            else if (t > 1)
                ans += string.Format("{0}-", tens[t]);
        case 1:
            int o = number % 10;
            ans += numbers[o];

            break;
        default:
            throw new ArgumentException("number");
    }
    return ans;
}

聪明的人畏缩不前，因为字符串[]应该在函数之外声明:好吧，它们是，这只是一个例子。

编译器失败，出现以下错误:

Control cannot fall through from one case label ('case 3:') to another
Control cannot fall through from one case label ('case 2:') to another

为什么?有没有什么方法能让这种行为不需要三个如果呢?