Mixin Demo

ILogger.cs

namespace MixinDemo
{
    public interface ILogger
    {
    }
}

Log.cs

using System;

namespace MixinDemo.Logger1.Log
{
    public static class Mixin
    {
        public static void Log(this ILogger logger, string message)
        {
            Console.WriteLine("Logger1 Log: " + message);
        }
    }
}

LogError.cs

using System;

namespace MixinDemo.Logger2.LogError
{
    public static class Mixin
    {
        public static void LogError(this ILogger logger, string message)
        {
            Console.WriteLine("Logger2 LogError: " + message);
        }
    }
}

Program.cs

using System;

namespace MixinDemo
{
    // Mix in the ILogger functionality required by the implementation of the Program class
    using Logger1.Log;
    using Logger2.LogError;

    class Program
    {
        ILogger logger = null; // OK to leave uninitialized since only extension methods will be called

        static void Main(string[] args)
        {
            new Program().Execute();
        }

        private void Execute()
        {
            try
            {
                logger.Log("Hello World");
                (null as object).GetType(); // error
            }
            catch (Exception ex)
            {
                logger.LogError(ex.Message);
            }
        }
    }
}