blocks|key|1485763|text|这只是一种允许将保留关键字声明为var的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1485764|void+Foo(int+@string)|code-block|syntax|javascript|1485765|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

It's just a way to allow declaring reserved keywords as vars.

<pre><code>void Foo(int @string)
</code></pre>

blocks|key|1485799|text|这将转义C#中的保留字。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1485800|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|$]]

This escapes reserved words in C#.

blocks|key|1485892|text|它允许您使用保留字，例如'public‘，作为变量名。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1485893|string+@public+=+"foo";|code-block|syntax|javascript|1485894|我不建议这样做，因为它会导致不必要的混乱。|1485895|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It allows you to use a reserved word, like 'public' for example, as a variable name.

<pre><code>string @public = "foo";
</code></pre>

I would not recommend this, as it can lead to unecessary confusion.

blocks|key|1485958|text|将@放在字符串前面告诉强制程序不处理在字符串中找到的转义序列。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1485959|来自the+documentation|offset|length|1485960|@-引号的优点是不会处理转义序列，这使得编写完全限定的文件名变得很容易：|1485961|@"c:\Docs\Source\a.txt"++//+rather+than+"c:\\Docs\\Source\\a.txt"|code-block|syntax|javascript|1485962|要在@引号的字符串中包含双引号，请使用双引号：|1485963|@"""Ahoy!""+cried+the+captain."+//+"Ahoy!"+cried+the+captain.|1485964|@符号的另一个用途是使用恰好是C#关键字的引用(/reference)标识符。有关详细信息，请参阅2.4.2+Identifiers。|1485965|entityMap|0|LINK|mutability|MUTABLE|url|http://msdn.microsoft.com/en-us/library/362314fe(VS.71).aspx)|1|http://msdn.microsoft.com/en-us/library/aa664670(VS.71).aspx)^0|0|2|H|0|0|0|0|0|0|1D|H|1|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@]|9|@$D|14|E|15|1|16]]|A|$]]|$1|F|3|G|5|6|7|17|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|18|8|@]|9|@]|A|$K|L]]|$1|M|3|N|5|6|7|19|8|@]|9|@]|A|$]]|$1|O|3|P|5|J|7|1A|8|@]|9|@]|A|$K|L]]|$1|Q|3|R|5|6|7|1B|8|@]|9|@$D|1C|E|1D|1|1E]]|A|$]]|$1|S|3|-4|5|6|7|1F|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]|10|$5|V|W|X|A|$Y|11]]]]

Putting @ in front of a string tells the compuler not to process escape sequences found within the string.

From <a href="http://msdn.microsoft.com/en-us/library/362314fe(VS.71).aspx" rel="noreferrer">the documentation</a>:

The advantage of @-quoting is that escape sequences are not processed, which makes it easy to write, for example, a fully qualified file name:

<pre><code>@"c:\Docs\Source\a.txt" // rather than "c:\\Docs\\Source\\a.txt"
</code></pre>

To include a double quotation mark in an @-quoted string, double it:

<pre><code>@"""Ahoy!"" cried the captain." // "Ahoy!" cried the captain.
</code></pre>

Another use of the @ symbol is to use referenced (/reference) identifiers that happen to be C# keywords. For more information, see <a href="http://msdn.microsoft.com/en-us/library/aa664670(VS.71).aspx" rel="noreferrer">2.4.2 Identifiers</a>.

blocks|key|1486034|text|最初的问题问了一个为什么要转义非保留字的原因。我想到的是，如果step在将来成为保留字，代码示例仍然可以编译。我想这对于代码生成器来说也是一个有效的选择。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1486035|entityMap^0|V|4|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

The original question asks for a reason why one would escape a not-reserved word. What comes to my mind is that if <code>step</code> would become a reserved word in future the code example would still compile. I guess it is also a valid option for code generators.

blocks|key|1486094|text|@符号与与language关键字相同的标识符一起使用。它有两个主要用途--与非C#代码互操作。在VB或IronPython等语言中，关键字与C#中的关键字不同，它们可能声明了名称与C#关键字匹配的类和属性。如果不存在此功能，则无法在C#中访问此代码。-机器生成的代码。如果代码生成器基于某些外部源(例如WSDL)生成代码，则生成器可以只在所有标识符前面加上@，而不检查和转换与C#关键字匹配的标识符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1486095|你确定你的案子不是第二个吗？|1486096|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

The @ sign is used with identifiers that are the same as language keywords. There are two main uses for this
 - interoperating with non-C# code. In languages like VB or IronPython the keywords are not the same as in C# and they may have declared classes and properties with names that match C# keywords. If this feature was not present this code would not be accessible in C#.
 - machine generated code. If a code generator generates code based on some external source (for example WSDL) the generator can just prefix all identifiers with @ and not check and convert identifiers that match C# keywords.

Are you sure that your case is not the second?

I've been working with some C# legacy code and I've been seeing a lot of @ symbols in front of variable names. What does this signify or do?

Currently I'm seeing it a lot in front of variables with common names that aren't reserved. E.g.:

<pre><code>MyProcedure(@step.LoadInstanceId, @step.ResultCode, @step.StatusCode);
</code></pre>

Given that step isn't a reserved word, is there any reason that they should be escaped?

What does placing a @ in front of a C# variable name do?

我一直在使用一些C#遗留代码，并且看到很多@符号出现在变量名的前面。这意味着什么或做了什么？目前，我经常在具有未保留名称的通用名称的变量前面看到它。例如：MyProcedure(@step.LoadInstanceId, @step.ResultCode, @step.StatusCode);鉴于该步骤不是保留字，是否...

问在C#变量名前面放一个@有什么作用？
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问在C#变量名前面放一个@有什么作用？
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