MEF Example

MEF.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
using System.Linq;
using System.Reflection;
using System.Text;

namespace ConsoleApplication1 {
    class Program {
        static void Main(string[] args) {
            var p = new PluginManager();
            p.LoadPlugins();

            foreach (var plugin in p.Plugins)
                Console.WriteLine(string.Format("{0}: {1}", plugin.Name, plugin.DoSomething("This is a test.")));

            Console.ReadLine();
        }
    }

    public class PluginManager {

        [ImportMany(typeof(IPlugin))]
        public List<IPlugin> Plugins { get; set; }

        public void LoadPlugins() {
            var catalog = new AssemblyCatalog(Assembly.GetExecutingAssembly());
            var container = new CompositionContainer(catalog);
            container.ComposeParts(this);
        }

    }

    public interface IPlugin {
        string Name { get; }
        string DoSomething(string input);
    }
    
    [Export(typeof(IPlugin))]
    public class PluginA:IPlugin {
        public string Name { get { return "Plugin A"; } }
        public string DoSomething(string input) {
            return input.ToUpperInvariant();
        }
    }

    [Export(typeof(IPlugin))]
    public class PluginB:IPlugin {
        public string Name { get { return "Plugin B"; } }
        public string DoSomething(string input) {
            return string.Format(">>>>{0}<<<<", input);
        }
    }

}