为什么类型＆QUOT; INT＆QUOT;永远不会等于“空”？ [英] Why type "int" is never equal to 'null'?

问题描述

int n == 0;

if (n == null)    
{  
    Console.WriteLine("......");  
}

这是真的，当然pression的结果（ñ== 0 ）始终是假的，因为类型的值 INT 永远等于空 INT？

Is it true that the result of expression (n == 0) is always false since a value of type int never equals to null of type int?

推荐答案

如果你希望你的整型变量允许空值，声明它是一个的可空类型：

If you want your integer variable to allow null values, declare it to be a nullable type:

int? n = 0;

请注意在？ INT之后，这意味着该类型的值可以是空。可空类型进行了介绍与.NET Framework V2.0版。

Note the ? after int, which means that type can have the value null. Nullable types were introduced with v2.0 of the .NET Framework.

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