Just a single snippet of code to work from, I included explanations in the comments. This is really a very easy to use feature in C# 3. Unfortunately you can’t create extension properties yet, but that will likely be coming soon.
namespace ExtensionMethods
{
//Note that this class is static, it must be to contain extension methods and
//it also can't reside inside another class.
public static class ExampleExtensionMethod
{
//This is the extension method
public static bool HasLetterAInIt(this string s)
{
//Just return if it contains the capital letter A as this is just an
//example
return s.Contains("A");
}
}
class Program
{
static void Main(string[] args)
{
//This will print false
Console.WriteLine("TEST".HasLetterAInIt().ToString());
//whilst this will print true
Console.WriteLine("AAHH!!".HasLetterAInIt().ToString());
}
}
}