How do I strip non-alphanumeric characters (including spaces) from a string?

Question

How do I strip non alphanumeric characters from a string and loose spaces in C# with Replace?

I want to keep a-z, A-Z, 0-9 and nothing more (not even \" \" spaces).<

Answer 1

The mistake made above was using Replace incorrectly (it doesn't take regex, thanks CodeInChaos).

The following code should do what was specified:

Regex reg = new Regex(@"[^\p{L}\p{N}]+");//Thanks to Tim Pietzcker for regex
string regexed = reg.Replace("Hello there(hello#)", "");

This gives:

regexed = "Hellotherehello"