blocks|key|2418433|text|在这种情况下，它在C#中的个人偏好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2418434|​|2418435|📷|atomic|offset|length|2418436|2418437|尤达条件|2418438|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://developer.qcloudimg.com/http-save/yehe-900000/dd1fcce583829600a001d5edd9e45ccb.jpg|imageAlt^0|0|0|0|1|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@$G|X|H|Y|1|Z]]|A|$]]|$1|I|3|C|5|6|7|10|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|11|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|S|T|-4]]]]

In this case, its personal preference in C#.

<img src="https://i.stack.imgur.com/Z0Zy8.jpg" alt="enter image description here">

Yoda Conditionals

blocks|key|2398253|text|在所有方面都完全一样。只是用相反的方式做同样的事情。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2398254|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Absolutely identical in all aspects. Just a reversed way of doing the same thing.

blocks|key|2418475|text|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2418476|是否存在性能差异，还是仅仅是个人偏好？|blockquote|2418477|2418478|2418479|不，绝对没有表现上的差别。这只是个人喜好的问题。|2418480|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|-4|4|5|6|J|7|@]|8|@]|9|$]]|$1|A|3|B|4|C|6|K|7|@]|8|@]|9|$]]|$1|D|3|-4|4|5|6|L|7|@]|8|@]|9|$]]|$1|E|3|-4|4|5|6|M|7|@]|8|@]|9|$]]|$1|F|3|G|4|5|6|N|7|@]|8|@]|9|$]]|$1|H|3|-4|4|5|6|O|7|@]|8|@]|9|$]]]|I|$]]

<blockquote>
 Is there a performance difference or is it just personal preference?
</blockquote>

No, absolutely no performance difference. It's only a matter of personal preference.

blocks|key|695241|text|这是C%2B%2B+days的雏形，在那里您可以使用=而不是==来意外地赋值变量，而且它仍然会通过编译器，因为您可以将几乎任何东西传递到C%2B%2B中的比较中。不要在C#中使用它，因为它不会允许您这样做。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|695242|有效C%2B%2B：|695243|if+(p+=+NULL)+//+p+gets+assigned+NULL+and+result+is+compared+to+0|695244|无效的C#：|695245|if+(p+=+null)+//+can+only+use+booleans+in+test|695246|entityMap^0|M|1|Q|2|0|0|0|1T|0|0|0|1A|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|Y|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|N|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|O|$]]

It's a rudiment from C++ days, where you could accidentally assign variable by using <code>=</code> instead of <code>==</code> and it would still pass the compiler cause you could pass almost anything into comparisons in C++. 
Do not use it in C#, cause it will not allow you to do so.

Valid C++:

<code>if (p = NULL) // p gets assigned NULL and result is compared to 0</code>

Invalid C#:

<code>if (p = null) // can only use booleans in test</code>

blocks|key|2398370|text|使用null+==+x可以防止意外错误地输入和遗漏一个等于符号，从而分配而不是测试一个值。您将最终得到不编译的null+=+x。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2398371|无论如何，使用Object.ReferenceEquals(x,+null)可能更好，因为它可以防止==被重载的情况。|2398372|entityMap^0|2|9|1J|8|0|7|V|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|R|8|@]|D|@]|E|$]]]|I|$]]

Using <code>null == x</code> prevents accidentally mistyping and missing out one equals symbol and therefore assigning rather than testing for a value. You would end up with <code>null = x</code> which would not compile.

In any case, using <code>Object.ReferenceEquals(x, null)</code> is probably better anyway, as it would prevent cases where == has been overloaded.

<blockquote>
 Possible Duplicate: 
 <a href="https://stackoverflow.com/questions/5854317/what-is-the-difference-between-these-bcondition-null-and-null-bcondition">What is the difference between these (bCondition == NULL) and (NULL==bCondition)?</a> 
</blockquote>



I have seen comparisons done both ways. Is there a performance difference or is it just personal preference?

I saw it being used in this answer:

<a href="https://stackoverflow.com/questions/271398/what-are-your-favorite-extension-methods-for-c-codeplex-com-extensionoverflow/833477#833477">What are your favorite extension methods for C#? (codeplex.com/extensionoverflow)</a>

Difference between null == x and x == null?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

 可能重复：我看到了两种方式的比较。是表现上的差异，还是仅仅是个人的偏好？我在这个答案中看到了它的用法：

问空== x和x == null之间的区别？
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问空== x和x == null之间的区别？EN