MEF CompositionClass - allows user to implement MEF into application using couple lines of code.

CpoDesign.Service.Core.Composition.cs

using System;
using System.ComponentModel.Composition;
using System.ComponentModel.Composition.Hosting;
using System.IO;

namespace CpoDesign.Service.Core
{
    /// <summary>
    /// MEF Compositon class
    /// </summary>
    /// <code>
    /// var path = AppDomain.CurrentDomain.BaseDirectory;
    /// var composition = new Composition();
    /// composition.ComposeContainer(path);
    /// composition.AddPart(this);
    /// composition.Compose();
    /// </code>
    public class Composition
    {
        private CompositionBatch _batch;
        private CompositionContainer _container;
        public void ComposeContainer(string path, bool hasPlugins = false)
        {
            AggregateCatalog catalog;

            if (hasPlugins)
            {
                catalog = new AggregateCatalog(
                    new DirectoryCatalog(Path.Combine(path, "Plugins")),
                    new DirectoryCatalog(path));
            }
            else
            {
                catalog = new AggregateCatalog(new DirectoryCatalog(path));
            }

            _container = new CompositionContainer(catalog);
        }

        public void AddPart<T>(T type)
        {
            if (_batch == null) _batch = new CompositionBatch();

            _batch.AddPart(type);
        }

        public void Compose()
        {
            try
            {
                _container.Compose(_batch);
            }
            catch (CompositionException ex)
            {
                foreach (var error in ex.Errors)
                {
                    Console.WriteLine(error.Description);
                }
                throw;
            }
        }

    }
}