好了，在给予dynamic_cast和多重继承之后，我想出了这个感谢 Anthony Williams 和 jogear.net

Well, after giving in to dynamic_cast and multiple inheritance, I came up with this thanks to Anthony Williams and jogear.net

class HandlerBase
{
public:
    virtual ~HandlerBase() {}
};

template<typename T> class Handler : public virtual HandlerBase
{
public:
    virtual void process(const T&)=0;
};

class MessageBase
{
public:
    virtual void dispatch(HandlerBase* handler) = 0;

    template<typename MessageType>
    void dynamicDispatch(HandlerBase* handler, MessageType* self)
    {
        dynamic_cast<Handler<MessageType>&>(*handler).process(*self);
    }
};

template<typename MessageType> class Message : public MessageBase
{
    virtual void dispatch(HandlerBase* handler)
    {
        dynamicDispatch(handler, static_cast<MessageType*>(this));
    }
};

class AlphaMessage : public Message<AlphaMessage>
{
};

class BravoMessage : public Message<BravoMessage>
{
};

class Sandbox : public Handler<AlphaMessage>, public Handler<BravoMessage>
{
public:
    void run()
    {
        MessageBase* alpha = new AlphaMessage;
        MessageBase* bravo = new BravoMessage;

        alpha->dispatch(this);
        bravo->dispatch(this);

        delete alpha;
        delete bravo;
    }
    virtual void process(const AlphaMessage&) {
        // cout << "Applying alpha\n";
    }

    virtual void process(const BravoMessage&) {
        // cout << "Applying bravo\n";
    }
};


int main()
{
    Sandbox().run();
    return 0;
}