@(at) 登录文件路径/字符串 [英] @(at) sign in file path/string

问题描述

可能的重复:
.NET 字符串前面的 @ 是什么?

我有以下代码:

new Attachment(Request.PhysicalApplicationPath + @"pdf" + pdfItem.Value)

@ 符号有什么作用?

推荐答案

与文件路径无关.它改变了字符串的转义行为.

It has nothing to do with filepath. It changes the escaping behavior of strings.

在以 @ 为前缀的字符串文字中，以 开头的转义序列被禁用.这对于文件路径很方便，因为 是路径分隔符，您不希望它开始转义序列.

In a string literal prefixed with @ the escape sequences starting with are disabled. This is convenient for filepaths since is the path separator and you don't want it to start an escape sequence.

在普通字符串中，您必须将 转义为 \，因此您的示例将类似于pdf\".但是由于它以 @ 为前缀，因此唯一需要转义的字符是 "(转义为 "")和 可以简单地出现.

In a normal string you would have to escape into \ so your example would look like this "pdf\". But since it's prefixed with @ the only character that needs escaping is " (which is escaped as "") and the can simply appear.

此功能对于包含 的字符串文字很方便，例如文件路径或正则表达式.

This feature is convenient for strings literals containing such as filepaths or regexes.

对于您的简单示例，增益不是那么大，但是您有完整路径 "C:\ABC\CDE\DEF" 然后 @"C:ABCCDEDEF" 看起来好多了.

For your simple example the gain isn't that big, but image you have a full path "C:\ABC\CDE\DEF" then @"C:ABCCDEDEF" looks a lot nicer.

对于正则表达式，这几乎是必须的.正则表达式通常包含几个 已经转义其他字符，如果您需要转义它们，通常会变得几乎不可读.

For regular expressions it's almost a must. A regex typically contains several escaping other characters already and often becomes almost unreadable if you need to escape them.

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