怎么去遍历接口上的类

如何去遍历接口下的类
假如我有一个接口叫IA，继承它的类有3个活着N个，我怎么去遍历这些类呢？
interface IA{}

class B:IA{}
class C:IA{}
class D: IA{}

我怎么去遍历这些类呢

[解决办法]
用这个就行了，
 List<IA> objectCollection = new List<IA>();
 objectCollection .Add(new B());
 objectCollection .Add(new C());
 objectCollection .Add(new D());

//如是不要它，就去掉

C# code

 objectCollection .Remove(index_intType );
[解决办法]
给你写了一个简单的控制台demo

C# code
 using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.ComponentModel.Composition;using System.ComponentModel.Composition.Hosting;using System.ComponentModel.Composition.Primitives;namespace ConsoleApplication1{    class Program    {        public static CompositionContainer Container = new CompositionContainer();                static void Main(string[] args)        {            mef_init();                      IAFactory Iafactory = new IAFactory();            //组合IA接口            Container.ComposeParts(Iafactory);                    var ias = Iafactory.IAs;            foreach (var IADemo in ias)            {                Console.WriteLine(IADemo.Export());                            }            Console.Read();        }        /// <summary>        /// 初始化MEF设置        /// </summary>        private static void mef_init()        {            var catalog = new AggregateCatalog();            catalog.Catalogs.Add(new DirectoryCatalog(@"."));            catalog.Catalogs.Add(new AssemblyCatalog(typeof(Program).Assembly));            Container = new CompositionContainer(catalog);               }    }    interface IA    {        string Export();    }    [Export(typeof(IA))]    class B : IA    {        public string Export()        {            return "Class=B";        }    }    [Export(typeof(IA))]    class C : IA    {        public string Export()        {            return "Class=C";        }    }     [Export(typeof(IA))]    class D : IA    {        public string Export()        {            return "Class=" + this.GetType().FullName;        }    }    class IAFactory    {             [ImportMany(typeof(IA))]        public IEnumerable<IA> IAs { get; set; }         }}