Estou tendo o problema descrito emesta mensagem no fórum.

Eu tenho um objeto que está hospedado em seu próprio AppDomain.

public class MyObject : MarshalByRefObject
{
    public event EventHandler TheEvent;
    ...
    ...
}

Gostaria de adicionar um manipulador a esse evento. O manipulador será executado em um AppDomain diferente. Meu entendimento é que tudo isso é bom, os eventos são entregues através desse limite magicamente, com o .NET Remoting.

Mas quando faço isso:

// instance is an instance of an object that runs in a separate AppDomain
instance.TheEvent += this.Handler ; 

... compila bem, mas falha em tempo de execução com:

System.Runtime.Remoting.RemotingException: 
     Remoting cannot find field 'TheEvent' on type 'MyObject'.

Por quê?

EDITAR: código-fonte do aplicativo de trabalho que demonstra o problema:

// EventAcrossAppDomain.cs
// ------------------------------------------------------------------
//
// demonstrate an exception that occurs when trying to use events across AppDomains.
//
// The exception is:
// System.Runtime.Remoting.RemotingException:
//       Remoting cannot find field 'TimerExpired' on type 'Cheeso.Tests.EventAcrossAppDomain.MyObject'.
//
// compile with:
//      c:\.net3.5\csc.exe /t:exe /debug:full /out:EventAcrossAppDomain.exe EventAcrossAppDomain.cs
//

using System;
using System.Threading;
using System.Reflection;

namespace Cheeso.Tests.EventAcrossAppDomain
{
    public class MyObject : MarshalByRefObject
    {
        public event EventHandler TimerExpired;
        public EventHandler TimerExpired2;

        public  MyObject() { }

        public void Go(int seconds)
        {
            _timeToSleep = seconds;
            ThreadPool.QueueUserWorkItem(Delay);
        }

        private void Delay(Object stateInfo)
        {
            System.Threading.Thread.Sleep(_timeToSleep * 1000);
            OnExpiration();
        }

        private void OnExpiration()
        {
            Console.WriteLine("OnExpiration (threadid={0})",
                              Thread.CurrentThread.ManagedThreadId);
            if (TimerExpired!=null)
                TimerExpired(this, EventArgs.Empty);

            if (TimerExpired2!=null)
                TimerExpired2(this, EventArgs.Empty);
        }

        private void ChildObjectTimerExpired(Object source, System.EventArgs e)
        {
            Console.WriteLine("ChildObjectTimerExpired (threadid={0})",
                              Thread.CurrentThread.ManagedThreadId);
            _foreignObjectTimerExpired.Set();
        }

        public void Run(bool demonstrateProblem)
        {
            try 
            {
                Console.WriteLine("\nRun()...({0})",
                                  (demonstrateProblem)
                                  ? "will demonstrate the problem"
                                  : "will avoid the problem");

                int delaySeconds = 4;
                AppDomain appDomain = AppDomain.CreateDomain("appDomain2");
                string exeAssembly = Assembly.GetEntryAssembly().FullName;

                MyObject o = (MyObject) appDomain.CreateInstanceAndUnwrap(exeAssembly,
                                                                          typeof(MyObject).FullName);

                if (demonstrateProblem)
                {
                    // the exception occurs HERE
                    o.TimerExpired += ChildObjectTimerExpired;
                }
                else
                {
                    // workaround: don't use an event
                    o.TimerExpired2 = ChildObjectTimerExpired;
                }

                _foreignObjectTimerExpired = new ManualResetEvent(false);

                o.Go(delaySeconds);

                Console.WriteLine("Run(): hosted object will Wait {0} seconds...(threadid={1})",
                                  delaySeconds,
                                  Thread.CurrentThread.ManagedThreadId);

                _foreignObjectTimerExpired.WaitOne();

                Console.WriteLine("Run(): Done.");

            }
            catch (System.Exception exc1)
            {
                Console.WriteLine("In Run(),\n{0}", exc1.ToString());
            }
        }



        public static void Main(string[] args)
        {
            try 
            {
                var o = new MyObject();
                o.Run(true);
                o.Run(false);
            }
            catch (System.Exception exc1)
            {
                Console.WriteLine("In Main(),\n{0}", exc1.ToString());
            }
        }

        // private fields
        private int _timeToSleep;
        private ManualResetEvent _foreignObjectTimerExpired;

    }
}