c++从不同线程中的非托管代码调用委托

Question

[提前致歉。我已经阅读了此处和 codeproject.com 上有关此主题的几篇帖子，但我仍然缺少一些内容。]

我有一个通知框架（类似于事件），作为用非托管 C++ 编写的遗留系统的一部分。我还有一个混合模式 DLL，其中包含向托管世界公开遗留功能的托管类。

CacheControlNotification 类是一个管理桥类，旨在将未管理事件转换为托管事件。它包含一个非托管 NativeCcmBridge 类，该类在遗留框架中注册以接收非托管消息。 NativeCcmBridge 将数据编组为托管类型，并将其传递到 CacheControlNotification，并在其中分派给感兴趣的托管方。

GetDelegateForFunctionPointer() 抛出 NotSupportedException：无法将委托从本机代码编组到除其主域之外的域中。

回调发生在源自本机代码的线程中。这个例外让我相信我的解决方案从根本上来说是有缺陷的。

任何帮助表示赞赏。谢谢。

罗伯特

public delegate void OnNotifyHandler ( ManagedCallbackMessage^ );

//
// Native class to marshal callback to managed code.   Callbacks
// in the native world are registered via an "ANativeHandler" type.
//
class NativeCcmBridge : public ANativeHandler
{
    private:
        //
        // Pointer to the managed delegate
        //
        IntPtr m_callbackPtr;


    public:
        NativeCcmBridge ( OnNotifyHandler^ callback )
        {
            m_callbackPtr = Marshal::GetFunctionPointerForDelegate(callback);
        }

        //
        // Provide implementation for pure virtual native handler
        //
        virtual void OnNotify (NativeCallbackMsg& nativeCallbackMsg)
        {
            // Convert the native message to a managed message
            ManagedCallbackMessage^ msg = new ManagedCallbackMessage( nativeCallbackMsg );

            // Now push the managed message via the delegate
            // throws NotSupportedException:  Delegates cannot be marshaled from native code into a domain other than their home domain.
            OnNotifyHandler^ callback = (OnNotifyHandler^)Marshal::GetDelegateForFunctionPointer(m_callbackPtr, OnNotifyHandler::typeid);
            callback( msg );
        }

};

//
// Managed Class to receive marshalled messages and 
// reissue in managed world.
//
public ref class CacheControlNotification
{
    public:
        CacheControlNotification()
        {
            m_callback = (OnNotifyHandler^) Delegate::CreateDelegate( OnNotifyHandler::typeid, this, "RaiseNotification" );
            m_bridge = new NativeCcmBridge( m_callback );

            // Register m_bridge the native mechanism
        }

        virtual ~CacheControlNotification () { this->!CacheControlNotification(); }
        !CacheControlNotification ()
        {
            delete m_bridge;
            m_bridge = nullptr;
        }

        event OnNotifyHandler^ OnNotify;

    protected:
        NativeCcmBridge* m_bridge;
        pin_ptr<OnNotifyHandler^> m_callback;

        void RaiseNotification ( CacheControlMessage^ msg )
        {
            OnNotify( msg );
        }
};