深入解析C++程序中激发事件和COM中的事件处理

// evh_native.cpp
#include 

[event_source(native)]
class CSource {
public:
  __event void MyEvent(int nValue);
};

[event_receiver(native)]
class CReceiver {
public:
  void MyHandler1(int nValue) {
   printf_s("MyHandler1 was called with value %d.\n", nValue);
  }

  void MyHandler2(int nValue) {
   printf_s("MyHandler2 was called with value %d.\n", nValue);
  }

  void hookEvent(CSource* pSource) {
   __hook(&CSource::MyEvent, pSource, &CReceiver::MyHandler1);
   __hook(&CSource::MyEvent, pSource, &CReceiver::MyHandler2);
  }

  void unhookEvent(CSource* pSource) {
   __unhook(&CSource::MyEvent, pSource, &CReceiver::MyHandler1);
   __unhook(&CSource::MyEvent, pSource, &CReceiver::MyHandler2);
  }
};

int main() {
  CSource source;
  CReceiver receiver;

  receiver.hookEvent(&source);
  __raise source.MyEvent(123);
  receiver.unhookEvent(&source);
}

MyHandler2 was called with value 123.
MyHandler1 was called with value 123.

// evh_server.h
#pragma once

[ dual, uuid("00000000-0000-0000-0000-000000000001") ]
__interface IEvents {
  [id(1)] HRESULT MyEvent([in] int value);
};

[ dual, uuid("00000000-0000-0000-0000-000000000002") ]
__interface IEventSource {
  [id(1)] HRESULT FireEvent();
};

class DECLSPEC_UUID("530DF3AD-6936-3214-A83B-27B63C7997C4") CSource;

// evh_server.cpp
// compile with: /LD
// post-build command: Regsvr32.exe /s evh_server.dll
#define _ATL_ATTRIBUTES 1
#include 
#include 
#include "evh_server.h"

[ module(dll, name="EventSource", uuid="6E46B59E-89C3-4c15-A6D8-B8A1CEC98830") ];

[coclass, event_source(com), uuid("530DF3AD-6936-3214-A83B-27B63C7997C4")]
class CSource : public IEventSource {
public:
  __event __interface IEvents; 

  HRESULT FireEvent() {
   __raise MyEvent(123);
   return S_OK;
  }
};

// evh_client.cpp
// compile with: /link /OPT:NOREF
#define _ATL_ATTRIBUTES 1
#include 
#include 
#include 
#include "evh_server.h"

[ module(name="EventReceiver") ];

[ event_receiver(com) ]
class CReceiver {
public:
  HRESULT MyHandler1(int nValue) {
   printf_s("MyHandler1 was called with value %d.\n", nValue);
   return S_OK;
  }

  HRESULT MyHandler2(int nValue) {
   printf_s("MyHandler2 was called with value %d.\n", nValue);
   return S_OK;
  }

  void HookEvent(IEventSource* pSource) {
   __hook(&IEvents::MyEvent, pSource, &CReceiver::MyHandler1);
   __hook(&IEvents::MyEvent, pSource, &CReceiver::MyHandler2);
  }

  void UnhookEvent(IEventSource* pSource) {
   __unhook(&IEvents::MyEvent, pSource, &CReceiver::MyHandler1);
   __unhook(&IEvents::MyEvent, pSource, &CReceiver::MyHandler2);
  }
};

int main() {
  // Create COM object
  CoInitialize(NULL);
  {
   IEventSource* pSource = 0;
   HRESULT hr = CoCreateInstance(__uuidof(CSource), NULL,     CLSCTX_ALL, __uuidof(IEventSource), (void **) &pSource);
   if (FAILED(hr)) {
     return -1;
   }

   // Create receiver and fire event
   CReceiver receiver;
   receiver.HookEvent(pSource);
   pSource->FireEvent();
   receiver.UnhookEvent(pSource);
  }
  CoUninitialize();
  return 0;
}

MyHandler1 was called with value 123.
MyHandler2 was called with value 123.

[id(1)] HRESULT MyEvent1([in] int value);
[id(2)] HRESULT MyEvent2([in] int value);

[coclass, event_source(com)]
class CSource : public IEventSource {
public:
  __event __interface IEvents;

  HRESULT FireEvent() {
   MyEvent1(123);
   MyEvent2(123);
   return S_OK;
  }
};

[coclass, event_receiver(com, true)]
class CReceiver {
public:
  HRESULT MyEvent1(int nValue) { // name and signature matches MyEvent1
   ...
  }
  HRESULT MyEvent2(E c, char* pc) { // signature doesn't match MyEvent2
   ...
  }
  HRESULT MyHandler1(int nValue) { // name doesn't match MyEvent1 (or 2)
   ...
  }
  void HookEvent(IEventSource* pSource) {
   __hook(IFace, pSource); // Hooks up all name-matched events 
                // under layout_dependent = true
   __hook(&IFace::MyEvent1, pSource, &CReceive::MyEvent1);  // valid
   __hook(&IFace::MyEvent2, pSource, &CSink::MyEvent2);  // not valid
   __hook(&IFace::MyEvent1, pSource, &CSink:: MyHandler1); // not valid
  }
};