Using the literal '@' with a string variable

Question

I have a helper class pulling a string from an XML file. That string is a file path (so it has backslashes in it). I need to use that string as it is... How can I use it like I would with the literal command?

Instead of this:

string filePath = @"C:\somepath\file.txt";

I want to do this:

string filePath = @helper.getFilePath(); //getFilePath returns a string

This isn't how I am actually using it; it is just to make what I mean a little clearer. Is there some sort of .ToLiteral() or something?

Answer 1

I don't think you have to worry about it if you already have the value. The @ operator is for when you're specifying the string (like in your first code snippet).

What are you attempting to do with the path string that isn't working?

Answer 2

I'm not sure if I understand. In your example: if helper.getFilePath() returns "c:\\somepath\\file.txt" , there will be no problem, since the @ is only needed if you are explicitely specifying a string with "".

When Functions talk to each other , you will always get the literal path. If the XML contains c:\\somepath\\file.txt and your function returns c:\\somepath\\file.txt , then string filePath will also contain c:\\somepath\\file.txt as a valid path.

Answer 3

The @"" just makes it easier to write string literals.

string (C# Reference, MSDN)

Verbatim string literals start with @ and are also enclosed in double quotation marks. For example:

@"good morning" // a string literal

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

@"c:\\Docs\\Source\\a.txt" // rather than "c:\\\\Docs\\\\Source\\\\a.txt"

One place where I've used it is in a regex pattern:

string pattern = @"\b[DdFf][0-9]+\b";

If you have a string in a variable, you do not need to make a "literal" out of it, since if it is well formed, it already has the correct contents.

Answer 4

In C# the @ symbol combined with doubles quotes allows you to write escaped strings. Eg

print(@"c:\mydir\dont\have\to\escape\backslashes\etc");

If you dont use it then you need to use the escape character in your strings.

http://msdn.microsoft.com/en-us/library/aa691090(VS.71).aspx

You dont need to specify it anywhere else in code. In fact doing so should cause a compiler error.

Answer 5

You've got it backwards. The @-operator is for turning literals into strings, while keeping all funky characters. Your path is already a string - you don't need to do anything at all to it. Just lose the @.

string filePath = helper.getFilePath();

Answer 6

从您的助手类返回的字符串不是文字字符串，因此您不需要使用“@”字符来删除反斜杠的行为。