Extension methods allow us to extend/add methods to existing types.

• These are static methods.
• These methods are called on the type being extended.

Extension Method

namespace MyConsoleApp
{
    public static class MyExtensionMethods
    {
        public static int WordCount(this String str)
        {
            return str.Split(new char[] {' ', '.', '?' }, StringSplitOptions.RemoveEmptyEntries).Length;
        }
    }
}

Extension Method Implementation

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            string test = "This is a test";
            Console.WriteLine(test.WordCount()); // OUTPUT: 4
        }
    }
}

Good To Know

• LINQ standard query operators are the most common extension methods.