如何比较操作适用于空中断？ [英] How does comparison operator works with null int?

问题描述

我开始学习可空类型，跑进以下行为。

I am starting to learn nullable types and ran into following behavior.

虽然试图为空的INT，我看到比较运营商给了我意想不到的结果。例如，在我的下面code，输出我得到的是的既和1相等。注意，它不打印空为好。

While trying nullable int, i see comparison operator gives me unexpected result. For example, In my code below, The output i get is "both and 1 are equal". Note, it does not print "null" as well.

        int? a = null;
        int? b = 1;

        if (a < b)
            Console.WriteLine("{0} is bigger than {1}", b, a);
        else if (a > b)
            Console.WriteLine("{0} is bigger than {1}", a, b);
        else
            Console.WriteLine("both {0} and {1} are equal", a, b);

我希望任何非负整数会比空时，我失去了一些东西在这里？

I was hoping any non-negative integer would be greater than null, Am i missing something here ?

感谢

推荐答案

根据 MSDN - 这是在页面的运营商部分：

According to MSDN - it's down the page in the "Operators" section:

当你使用可空类型执行比较，如果可空类型之一的值是零，而另一个则不然，所有比较评估为假，除了！=

"When you perform comparisons with nullable types, if the value of one of the nullable types is null and the other is not, all comparisons evaluate to false except for !="

因此​​，无论 A＆GT; b 和 A＆LT; b 评估为假，因为 A 为空...

So both a > b and a < b evaluate to false since a is null...

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