检查空，哪个更好？ ＆QUOT;空==＆QUOT;或QUOT; == NULL＆QUOT; [英] Checking for null, which is better? "null ==" or "==null"

问题描述

杜佩：<一href="http://stackoverflow.com/questions/302701/null-difference">http://stackoverflow.com/questions/302701/null-difference

一个终身前，我碰到了解释，以下是不相等的（在C＃）的一篇​​文章：

A lifetime ago I came across an article that explained that the following were not equal (in c#):

if (o == null) {}
if (null == o) {}

文章解释，后者是preferred因为它导致更准确的测试。我一直在编码一样，自从。现在我明白了这么多我一直在寻找的物品，或其他喜欢它，来看看具体的调查结果，但是我无法找到关于这个问题的任何东西。

The article explained that the latter was preferred because it resulted in a more accurate test. I've been coding like that ever since. Now that I understand so much more I was looking for the article, or another like it, to see what the exact findings were, but I can't find anything on the subject.

思考？有区别吗？乍一看会说不。但谁知道在IL和C＃编写的肠子会发生什么。

Thoughts? Is there a difference? First glance would say no. But who knows what happens in the bowels of IL and C# compilation.

推荐答案

这是一个老习惯，以prevent你键入如果（O = NULL）。如果（空= O）是一个语法错误。一种毫无意义在C＃中，因为空值，所以以往任何时候都被迫布尔值。

it's an old habit to prevent you from typing if (o = null). if (null = o) is a syntax error. kind of pointless in C#, because null values aren't ever coerced into booleans.

这篇关于检查空，哪个更好？ ＆QUOT;空==＆QUOT;或QUOT; == NULL＆QUOT;的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！