WCF服务回调类字段为Null

在过去的一年里，我学到了很多关于WCF的知识，但由于我不是每天都使用它，我仍然知道它很危险。我的例子太复杂了，无法展示能说明我全部问题的东西，我很乐意展示我所拥有的那些你会觉得有用的部分。我有一个双工服务，并构建了一个名为HostedTransactionServiceProcess的类，该类封装了服务调用，这样任何使用它的客户端级类都不必理解使用WCF服务的复杂性。它封装调用的服务也可以通过回调事件进行通信。问题往往是服务操作和接收回调事件之间的协调。每当服务调用回调事件时，HostedTransactionServiceProcess的类级属性/字段值都为null。我认为这是有道理的，因为创建从服务到客户端的通道/代理留给了服务，并且在创建从客户端到服务的通道/代理人时不允许我们有那么多的控制。因此，如果它实例化了回调代理，那么一切都会默认，就好像这些值从未被修改过一样。

首先，这是正确的吗？其次，我该如何解决它？

我能够通过创建一个可以在进程间工作的命名EventWaitHandle来解决使用EventWaitHandler的需求，但我仍然需要在操作调用和回调事件调用之间看到类中的其他属性/字段数据。

再次，我可以根据需要提供更多信息，只需让我知道！

编辑：我试图将事情简化为一个不可行的类，至少应该说明我的问题。也许这会有所帮助？

 [CallbackBehavior(UseSynchronizationContext = false, ConcurrencyMode = ConcurrencyMode.Multiple, IncludeExceptionDetailInFaults = true)]
public class HostedTransactionServiceProcess : ServiceProcess<IHostedTransactionService, HostedTransactionServiceInvoker, ConfigurationDuplexChannelFactory<IHostedTransactionService>>, IHostedTransactionServiceProcess, IHostedTransactionCallbackService
{
    #region Properties
    private ICADSession _cadSession;
    public ICADSession CADSession
    {
        get { return _cadSession; }
        set { _cadSession = value; }
    }

    #endregion
    #region Operations
    public void Commit(ICADSession cadSession, IEnumerable<IDTOEntity> dtoEntityCollection, IDTODocument dtoDocument, IDTOOperationLock operationLock)
    {
        lock (_serviceInvokerLock)
        {
            //Since the callback session will be instantiated by the WCF Service, any fields/properties in this class will be instantiated to null.
            //This is because the Service is instantiating its own instance, creating its own proxy, based on the applied callback interface contract
            //To work around this so that a call to the CAD System can wait until the CAD System responds back through the WCF Service, a named, inter-process
            //EventWaitHandle will be used
            using (EventWaitHandle waitHandle = ServiceWaitHandleHelper.StartNew(false, EventResetMode.AutoReset, cadSession, "Commit"))
            {
                //Set a local value... the issue is that this will end up null when the callback event is called!!!!!
                //This seems to be because this instance making the Commit() call is different from the callback instance created to make the OnCommitted() call!!!
                this.CADSession = cadSession;
                //Make the proxy operation call
                this.ServiceInvoker.Execute(serviceProxy => serviceProxy.Commit(cadSession, dtoEntityCollection, dtoDocument, operationLock));
                //The lock will not be released for the next Commit() operation call until the entire commit process is completed or the operation times out.
                waitHandle.WaitOne(TimeSpan.FromMilliseconds(MAX_OPERATION_TIMEOUT));
            }
        }
    }
    //The WCF Service Callback will call this
    public void OnCommitted(ICADSession cadSession, IEnumerable<IDTOEntity> entityCollection, IDTODocument dtoDocument, IDTOOperationLock operationLock)
    {
        //First allow the Commit() operation to continue
        EventWaitHandle waitHandle = ServiceWaitHandleHelper.GetExisting(cadSession, "Commit");
        if (waitHandle != null && this.CADSession == cadSession)  //!!!!!! Here is the issue!!!  Even though this.CADSession was set to a value, the callback instance says it is null!!!
            waitHandle.Set();
        else
            return;
    }
    #endregion
}