C# 使用MEF动态加载不同的userControl,并实现不同userControl之间通信

 public partial class frmMain : Form
    {
        private void initMEF()
        {
            AggregateCatalog aggregateCatalog = new AggregateCatalog();//声明一个集合
            AssemblyCatalog assemblyCatalog = new AssemblyCatalog(Assembly.GetExecutingAssembly());//声明当前应用程序的cataLog
            aggregateCatalog.Catalogs.Add(assemblyCatalog);//将当前应用程序的catalog加入到该集合中
            CompositionContainer compositionContainer = new CompositionContainer(aggregateCatalog);//声明一个容器
            compositionContainer.ComposeParts(this);//创建组件
            
        }
        [Import("user")]
        private UserControlTest userControlTest { set; get; }
        public frmMain()
        {
            InitializeComponent();
            initMEF();//初始化MEF
            panel1.Controls.Clear();
            panel1.Controls.Add(userControlTest);
            EventBroker eventBroker = new EventBroker();
            eventBroker.Register(userControlTest);
            eventBroker.Register(this);
           
        }
        [EventSubscription(EventTopics.firstEvent, typeof(Background))]
        public void receiver(object obj, EventArgs args)
        {
            //System.Threading.Thread.Sleep(3000);
            MessageBox.Show("收到消息了");
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            label1.Text = DateTime.Now.ToString("hh:mm:ss.fff");
        }
    }

[Export("user")]
    public partial class UserControlTest : UserControl
    {
        public UserControlTest()
        {
            InitializeComponent();
        }
        [EventPublication(EventTopics.firstEvent)]
        public event EventHandler testEvent;

        private void btnTest_Click(object sender, EventArgs e)
        {
            testEvent(this,EventArgs.Empty);
            //System.Threading.Thread.Sleep(3000);
        }

    }

 public class EventTopics
    {
       public const string firstEvent = "test";
    }