How do I extend the String class?

Question

Extending core classes in javascript is dead easy. I get the impression it's not quite so easy in C#. I was wanting to add some things to the String class so that I could do stuff like:

string s = "the cat's mat sat";
string sql = s.smartsingleQuote();

thus giving me

the cat''s mat sat

Is that even feasible, or do I have to write a function for that?

Answer 1

Yes you can do this, with an extension method. It'll look something like that:

public static class NameDoesNotMatter {
   public static string smartSingleQuote(this string s) {
      string result = s.Replace("'","''");
      return result;
   } 
}

The magic is the keyword "this" in front of the first argument. Then you can write your code and it'll work:

string s = "the cat's mat sat";
string sql = s.smartsingleQuote();