What characters need to be escaped in .NET Regex?

Question

In a .NET Regex pattern, what special characters need to be escaped in order to be used literally?

Answer 1

I don't know the complete set of characters - but I wouldn't rely on the knowledge anyway, and I wouldn't put it into code. Instead, I would use Regex.Escape whenever I wanted some literal text that I wasn't sure about:

// Don't actually do this to check containment... it's just a little example. public bool RegexContains(string haystack, string needle) {     Regex regex = new Regex("^.*" + Regex.Escape(needle) + ".*$");     return regex.IsMatch(haystack); } 

Answer 2

Here is the list of characters that need to be escaped to use them as normal literals:

1. Opening square bracket [
2. Backslash \
3. Caret ^
4. Dollar sign $
5. Period or dot .
6. Vertical bar or pipe symbol |
7. Question mark ?
8. Asterisk or star *
9. Plus sign +
10. Opening round bracket ( and the closing round bracket )
11. Opening curly bracket {
12. Pound/Hash sign #

These special characters are often called "metacharacters".

But, I agree with Jon to use Regex.Escape instead of hardcoding these character in code.