Do I need to escape backslash in a config file?

Question

I have a config file, myapp.exe.config. In the file I have an attribute with a fullpath filename as the value.

<add key="InfoFile" value="c:\temp\info.txt" />

It seems to work if I use a single or double backslash. That is,

<add key="InfoFile" value="c:\\temp\\info.txt" />

works also. What is the correct way to do this?

Solution 1

You don't need that. Anything within an attribute value is character data.

Since you're reading these values using C#, they'll get escaped as if they would be a literal path string in code.

Anyway, you might want to know that C# has @ operator to declare verbatim strings, meaning that you don't need to escape backslashes when using literal paths in code:

string somePath = @"C:\blah\blih\bluh.txt";

Solution 2

A backslash has no special meaning in XML, so they should not be escaped.

Besides, if you would escape the backslashes in XML you would not use \\, you would use \.

The reason that it works with double backslashes also is that the file system is forgiving. You can use the path c:\\temp\\info.txt to reach the file c:\temp\info.txt.

Solution 3

Basically URL or URI holds single slash \ so, its better to use single slash. The problem comes while writing code, but in XML there is no problem to use single slash.

Comments

[leppie]

The filesystem is not forgiving. You can have as many \ as you want. Try it on the command line. Heck even URL's support that! Try stackoverflow.com/////////////////questions///////////////…

[smoore4]

I believe the question is which way is correct if you are setting the string like this: string m_path = ConfigurationManager.AppSettings["InfoFile"].ToString(); You can't add "@" at that point.

[Matías Fidemraizer]

@SQLDBA Why do you have such conclusion? :/

[smoore4]

Because the question starts "I have a config file..." Are you saying you can do this?? <add key="InfoFile" value=@"c:\temp\info.txt" /> I don't think so. Of course you can do what you are saying in direct code-behind, but if you are reading it from app.config, which the OP is doing, then it is actually just single slashes and not double.

[Matías Fidemraizer]

@SQLDBA I believe you're misunderstanding the OP... The OP is clearly talking about the XML configuration file. I remember that suggested verbatim strings just for the sake of giving him some hidden gem that the OP wouldn't know before. That's all.

[smoore4]

app.config (one of the question tags) is an XML file format, just like web.config but for console applications mostly.

[Matías Fidemraizer]

@SQLDBA Isn't this looping the loop? :/