CODEWITHSUNDEEP
c#string
naspinski
naspinski

Reputation: 34717

Using the literal '@' with a string variable

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?

Upvotes: 7

Views: 27233

Answers (6)

Michael Stum
Michael Stum

Reputation: 181124

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.

Upvotes: 4

crashmstr
crashmstr

Reputation: 28583

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.

Upvotes: 3

Gary Willoughby
Gary Willoughby

Reputation: 52608

The string returned from your helper class is not a literal string so you don't need to use the '@' character to remove the behaviour of the backslashes.

Upvotes: 1

Sander
Sander

Reputation: 26374

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();

Upvotes: 1

Jim Burger
Jim Burger

Reputation: 4547

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

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.

Upvotes: 2

brock.holum
brock.holum

Reputation: 3213

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?

Upvotes: 14

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