Why is my Dictionary adding extra escape character

Question

App.config:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="1" value="An error occured.\r\nPlease try again later." />
  </appSettings>
</configuration>

Code:

Dictionary<string, string> keyValuePairs = new Dictionary<string, string>();
string key = "1";

keyValuePairs.Add(key, ConfigurationManager.AppSettings["key"]);

if (keyValuePairs.ContainsKey(key))
{
  // when I hover over the object, keyValuePairs, in my debugger, I see, "An error occured.\r\nPlease try again later."
  string value1 = keyValuePairs[key];
  // now when I hover over the local variable, value, I see, "An error occured.\\r\\nPlease try again later."
}

I'm curious as to why the above code adds escape characters to "\r\n" to make it "\r\n"

I'd also like to know how to avoid getting the extra "\" characters.

Answer 1

The dictionary isn't doing anything to your string. The debugger, or more specifically the expression evaluator, will alter the format of a displayed string when it contains newline characters. The end goal is to make it display better on the single line the debugger typically has for values.

I recently did a blog post which goes into detail about what the debugger does and the reason behind the design

• http://blogs.msdn.com/b/jaredpar/archive/2010/06/08/newlines-in-the-immediate-window.aspx

EDIT

I believe there is a bug in your sample code. I think you left at @ symbol off of the value in the add of the Dictionary. Without the @ symbol I do not get your repro but with it I do. Assuming the @ is missing though ...

The reason why you see the string with extra escapes is that the debugger always displays strings as string literals and not verbatim strings. In a string literal you need the double escape to match the equivalent code in the verbatim string. Hence \n becomes \\n

Answer 2

If you are reading the string from the app.config, I assume it's something like the following:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="errorString" value="An error occured.\r\nPlease try again later."/>
  </appSettings>
</configuration>

In which case your sample code should look like this:

keyValuePairs.Add("1", @"An error occured.\r\nPlease try again later.");

And from there it should be obvious why the debugger is displaying as it does (especially if you read JaredPar's answer.

You're better off using a resource dictionary for storing the string, which will easily let you insert newline characters in the VS editor.

Edit: Just on a whim, I tried the following:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="errorString" value="An error occured.
Please try again later."/>
  </appSettings>
</configuration>

Compiled fine and produced the correct results.