c# - Replace single backslash with double backslash

Question

It seems simple enough, right? Well, I don't know.

Here's the code I'm trying:

input = Regex.Replace(input, "", "");

However, I'm receiving an error,

ArgumentException was unhandled - parsing "" - Illegal at end of pattern.

How do I do this?

Answer 1

The first one should be "", not "". It works like this:

• You have written "".
• This translates to the sequence in a string.
• The regex engine then reads this, which translates as backslash which isn't escaping anything, so it throws an error.

With regex, it's much easier to use a "verbatim string". In this case the verbatim string would be @"". When using verbatim strings you only have to consider escaping for the regex engine, as backslashes are treated literally. The second string will also be @"", as it will not be interpreted by the regex engine.