.net remoting 中棘手的问题

Question

请问高人：
用.net remoting 实现“远程的事件”。
但是我在visual studio 2005调试的时候出现：
Type System.DelegateSerializationHolder and the types derived from it (such as System.DelegateSerializationHolder) are not permitted to be deserialized at this security level.
在注册事件的时候：            bcaster.MessageArrived +=new MessageArrivedHandler(eventWrapper.LocallyHandleMessageArrived);
下面没有办法运行了，请高手指点一二，不胜感激。
全部代码如下：
Interface:
using System;
using System.Collections.Generic;
using System.Text;
namespace General
{
    public delegate void MessageArrivedHandler(String msg);
    public interface IBroadcaster
    {
        void BroadcastMessage(String msg);
        event MessageArrivedHandler MessageArrived;
    }
    public class BroadcastEventWrapper : MarshalByRefObject
    {
        public event MessageArrivedHandler MessageArrivedLocally;        public void LocallyHandleMessageArrived(String msg)
        {
            // forward the message to the client
            MessageArrivedLocally(msg);
        }        public override object InitializeLifetimeService()
        {
            // this object has to live "forever"
            return null;
        }
    }
}
Client:
using System;
using System.Runtime.Remoting;
using General;
//using RemotingTools; // RemotingHelpernamespace EventListener
{
    class EventListener
    {
        static void Main(string[] args)
        {
            String filename = "Client.exe.config";
            RemotingConfiguration.Configure(filename,false);            IBroadcaster bcaster = (IBroadcaster)Activator.GetObject(typeof(IBroadcaster), "http://localhost:5555/Broadcaster.soap");
               
//            IBroadcaster bcaster =
  //             (IBroadcaster)RemotingHelper.GetObject(typeof(IBroadcaster));            // this one will be created in the client's context and a
            // reference will be passed to the server
            BroadcastEventWrapper eventWrapper = new BroadcastEventWrapper();            // register the local handler with the "remote" handler
            eventWrapper.MessageArrivedLocally += new MessageArrivedHandler(HandleMessage);            Console.WriteLine("Registering event at server");
            bcaster.MessageArrived +=new MessageArrivedHandler(eventWrapper.LocallyHandleMessageArrived);            Console.WriteLine("Event registered. Waiting for messages.");
            Console.ReadLine();
        }        public static void HandleMessage(String msg)
        {
            Console.WriteLine("Received: {0}", msg);
        }
    }
}配置文件：
<configuration>
  <system.runtime.remoting>
    <application>      <channels>
         <channel ref="http"/>
      </channels>      <client>
        <wellknown type="General.IBroadcaster, General"
                    url="http://localhost:5555/Broadcaster.soap" />
      </client>    </application>
  </system.runtime.remoting>
</configuration>
//------------
还有个客户端的帮助类（不过我没有用，可以用注释的代码替换）
using System;
using System.Collections;
using System.Runtime.Remoting;namespace RemotingTools
{
    public class RemotingHelper
    {
        private static bool _isInit=false;
        private static IDictionary _wellKnownTypes;
        public static Object GetObject(Type type)
        {
            if (!_isInit) InitTypeCache();
            WellKnownClientTypeEntry entr =(WellKnownClientTypeEntry)_wellKnownTypes[type];
            if (entr == null)
            {
                throw new RemotingException("Type not found!");
            }
            return Activator.GetObject(entr.ObjectType, entr.ObjectUrl);
        }
        //-- HELP
        public static void InitTypeCache()
        {
            _wellKnownTypes = new Hashtable();
            foreach (WellKnownClientTypeEntry entr in RemotingConfiguration.GetRegisteredWellKnownClientTypes())
            {
                _wellKnownTypes.Add(entr.ObjectType, entr);
            }
        }
    }
}//--------------
Server:
using System;
using System.Runtime.Remoting;
using System.Threading;
using General;
namespace Server
{    public class Broadcaster : MarshalByRefObject, IBroadcaster
    {        public event General.MessageArrivedHandler MessageArrived;        public void BroadcastMessage(string msg)
        {
            Console.WriteLine("Will broadcast message: {0}", msg);
            SafeInvokeEvent(msg);
        }        private void SafeInvokeEvent(String msg)
        {
            // call the delegates manually to remove them if they aren't
            // active anymore.
            if (MessageArrived == null)
            {
                Console.WriteLine("No listeners");
            }
            else
            {                Console.WriteLine("Number of Listeners: {0}",
                                      MessageArrived.GetInvocationList().Length);                MessageArrivedHandler mah = null;                foreach (Delegate del in MessageArrived.GetInvocationList())
                {
                    try
                    {
                        mah = (MessageArrivedHandler)del;
                        mah(msg);
                    }
                    catch (Exception)
                    {
                        Console.WriteLine("Exception occured, will remove Delegate");
                        MessageArrived -= mah;
                    }
                }
            }
        }        public override object InitializeLifetimeService()
        {
            // this object has to live "forever"
            return null;
        }
    }    class ServerStartup
    {
        static void Main(string[] args)
        {
            String filename = "server.exe.config";
            RemotingConfiguration.Configure(filename,false);            Console.WriteLine("Server started, press <return> to exit.");
            Console.ReadLine();
        }
    }
}

Answer 1

自己顶一下
在.Net Framework1.1中2.0应该没改变，微软对序列化的安全级别进行了限制。有关委托和事件的序列化、反序列化默认是禁止的，所以我们应该将TypeFilterLevel的属性值设置为Full枚举值

Answer 2

private void StartServer()
{
 BinaryServerFormatterSinkProvider serverProvider = new 
  BinaryServerFormatterSinkProvider();
 BinaryClientFormatterSinkProvider clientProvider = new 
  BinaryClientFormatterSinkProvider();
 serverProvider.TypeFilterLevel = TypeFilterLevel.Full; IDictionary props = new Hashtable();
 props["port"] = 8080;
    HttpChannel channel = new HttpChannel(props,clientProvider,serverProvider);
 ChannelServices.RegisterChannel(channel); Obj = new BroadCastObj();
 ObjRef objRef = RemotingServices.Marshal(Obj,"BroadCastMessage.soap"); 
}注意语句serverProvider.TypeFilterLevel = TypeFilterLevel.Full；此语句即设置序列化安全级别的。要使用TypeFilterLevel属性，必须申明命名空间：
using System.Runtime.Serialization.Formatters;

Answer 3

我的问题解决了,主要参考了如下的网页,介绍的比较详细,遇到同样问题的朋友可以参考一下.
http://wayfarer.cnblogs.com/articles/75213.html