var catalog = new AggregateCatalog();

catalog.Catalogs.Add(new DirectoryCatalog("."));

var container = new CompositionContainer(catalog);

var catalog = new AggregateCatalog();

catalog.Catalogs.Add(new AssemblyCatalog(Assembly.GetExecutingAssembly()));

catalog.Catalogs.Add(new DirectoryCatalog("."));

var container = new CompositionContainer(catalog);

public void AssembleCalculatorComponents()

        {

            string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Plugins");

            Console.WriteLine(path);

            //Check the directory exists

            if (!Directory.Exists(path))

            {

                Directory.CreateDirectory(path);

            }

            Console.WriteLine(path);

            string assemblyName = Assembly.GetEntryAssembly().FullName;

            Console.WriteLine(assemblyName);

            //Create an assembly catalog of the assemblies with exports

            var catalog = new AggregateCatalog(

                new AssemblyCatalog(Assembly.GetExecutingAssembly().Location),

                new AssemblyCatalog(Assembly.Load(assemblyName)),

                new DirectoryCatalog(path, "*.dll"));

            //Create a composition container

            var container = new CompositionContainer(catalog);

            container.ComposeParts(this);