I am posting this as my answer so it stands out to other reading the questions.
As has been pointed out in the helpful comments to my question, it is clear that regex is not a good tool for finding strings in C# code. I could have written a simple “parser” in the time I spent reminding my self of the regex syntax. – (Parser is a over statement as there are no “ in comments etc, it is my source code I am dealing with.)
This seems to sums it up well:
Some people, when confronted with a problem, think “I know, I'll use
regular expressions.” Now they have two problems.
However until it breaks on my code I will use the regular expression Blixt has posted, but if it give me problems I will not spend match time trying to fix it before writing my own parser. E.g as a C# string it is
@"@Q(?:[^Q]+|QQ)*Q|Q(?:[^Q\\]+|\\.)*Q".Replace('Q', '\"')
Update, the above regEx had problem, so I just wrote my own parser, including writing unit tests it took about 2 hours to write the parser. That's I lot less time then I spend just trying to find (and test) a pre-canned Regex on the web.
The problem I see to have, is I tend to avoid Regex and just write the string handling code my self, then have a lot of people claim I am wasting the client’s money by not using Regex. However whenever I try to use Regex what seems like a simple match pattern becomes match harder quickly. (None the on-line articles on using Regex in .net that I have read, have a good instruction that make it clear when NOT to use Regex. Likewise with it’s MSDN documentation)
Lets see if we can help solve this problem, I have just created a stack overflow questions “When not to use Regex”
