.NET 4.0 Generics Beginner's Guide

Time for action – creating an Extension method

Let's say that you have a List of strings and you want to find out how many match a given regular expression pattern. This is a very common activity:

1. Create a class library project. Call it StringEx. We are trying to extend string class functionalities, so I named it StringEx.
2. Rename the generated class as StringExtenstions.cs.
3. Mark the class as static:

   public static class StringExtensions

4. Add the following using directive to the header of the class:

   using System.Text.RegularExpressions;

5. Add the following code snippet as the method body:

   public static bool IsMatching(this string input, string pattern)
   {
     return Regex.IsMatch(input, pattern,RegexOptions.CultureInvariant);
   }

What just happened?

We just created ...