问在没有委托的情况下，GCHandle不能跨AppDomains:解决方案传递？

EN

using System;
using System.Runtime.InteropServices;
using System.Threading;

namespace ConsoleApplication
{
    public class Program
    {
        [ComVisible(true)]
        [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)] // late binding only
        public interface ITest
        {
            void Report(string step);
        }

        [ComVisible(true)]
        [ClassInterface(ClassInterfaceType.None)]
        [ComDefaultInterface(typeof(ITest))]
        public class ComObject: MarshalByRefObject, ITest
        {
            public void Report(string step)
            {
                Program.Report(step);
            }
        }

        public static void Main(string[] args)
        {
            var obj = new ComObject();
            obj.Report("Object created.");

            System.AppDomain domain = System.AppDomain.CreateDomain("New domain");

            // via GCHandle
            var gcHandle = GCHandle.Alloc(obj);
            domain.SetData("gcCookie", GCHandle.ToIntPtr(gcHandle));

            // via COM GIT
            var git = (ComExt.IGlobalInterfaceTable)(Activator.CreateInstance(Type.GetTypeFromCLSID(ComExt.CLSID_StdGlobalInterfaceTable)));
            var comCookie = git.RegisterInterfaceInGlobal(obj, ComExt.IID_IUnknown);
            domain.SetData("comCookie", comCookie);

            // via COM CCW
            var unkCookie = Marshal.GetIUnknownForObject(obj);
            domain.SetData("unkCookie", unkCookie);

            // invoke in another domain
            domain.DoCallBack(() =>
            {
                Program.Report("Another domain");

                // trying GCHandle - fails
                var gcCookie2 = (IntPtr)(System.AppDomain.CurrentDomain.GetData("gcCookie"));
                var gcHandle2 = GCHandle.FromIntPtr(gcCookie2);
                try
                {
                    var gcObj2 = (ComObject)(gcHandle2.Target);
                    gcObj2.Report("via GCHandle");
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }

                // trying COM GIT - works
                var comCookie2 = (uint)(System.AppDomain.CurrentDomain.GetData("comCookie"));
                var git2 = (ComExt.IGlobalInterfaceTable)(Activator.CreateInstance(Type.GetTypeFromCLSID(ComExt.CLSID_StdGlobalInterfaceTable)));
                var obj2 = (ITest)git2.GetInterfaceFromGlobal(comCookie2, ComExt.IID_IUnknown);
                obj2.Report("via GIT");

                // trying COM CCW
                var unkCookie2 = (IntPtr)(System.AppDomain.CurrentDomain.GetData("unkCookie"));
                // this casting works because we derived from MarshalByRefObject
                var unkObj2 = (ComObject)Marshal.GetObjectForIUnknown(unkCookie2);
                obj2.Report("via CCW");
            });

            Console.ReadLine();
        }

        static void Report(string step)
        {
            Console.WriteLine(new
                {
                    step,
                    ctx = Thread.CurrentContext.GetHashCode(),
                    threadId = Thread.CurrentThread.ManagedThreadId,
                    domain = Thread.GetDomain().FriendlyName,
                });
        }

        public static class ComExt
        {
            static public readonly Guid CLSID_StdGlobalInterfaceTable = new Guid("00000323-0000-0000-c000-000000000046");
            static public readonly Guid IID_IUnknown = new Guid("00000000-0000-0000-C000-000000000046");

            [ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid("00000146-0000-0000-C000-000000000046")]
            public interface IGlobalInterfaceTable
            {
                uint RegisterInterfaceInGlobal(
                    [MarshalAs(UnmanagedType.IUnknown)] object pUnk,
                    [In, MarshalAs(UnmanagedType.LPStruct)] Guid riid);

                void RevokeInterfaceFromGlobal(uint dwCookie);

                [return: MarshalAs(UnmanagedType.IUnknown)]
                object GetInterfaceFromGlobal(
                    uint dwCookie,
                    [In, MarshalAs(UnmanagedType.LPStruct)] Guid riid);
            }
        }
    }
}