IUnknown *pUnk = NULL;

IObject *pObject = NULL;

CoInitialize(NULL);

CoCreateInstance(CLSID_Object, CLSCTX_INPROC_SERVER, NULL, IDD_Unknown, (void**)&pUnk);

pUnk->QueryInterface(IID_IObject, (void**)&pObject);

pUnk->Release();

pObject->Func();

pObject->Release();

CoUninitialize();

 

CoCreateInstance的内部:

CoCreateInstance(....)

{ 　　....... 　　IClassFactory *pClassFactory=NULL;

    //先获得类工厂对象①

　　CoGetClassObject(CLSID_Object, CLSCTX_INPROC_SERVER, NULL, IID_IClassFactory, (void **)&pClassFactory);

    //再通过类工厂对象创建组件并且得到IUnknown指针。②

　　pClassFactory->CreateInstance(NULL, IID_IUnknown, (void**)&pUnk); 　　pClassFactory->Release(); 　　........ }

 

//①-------------------

CoGetClassObject的内部:

CoGetClassObject(.....)

{ 　　//通过查注册表CLSID_Object，得知组件DLL的位置、文件名 　　//使用LoadLibrary装入DLL库 　　//使用函数GetProcAddress( "DllGetClassObject" )得到DLL库中函数DllGetClassObject的函数指针。 　　//调用DllGetClassObject }

DllGetClassObject是用来获得类工厂对象的，只有先得到类工厂才能去创建组件。

DllGetClassObject代码:

HRESULT_export  PASCAL DllGetClassObject (REFCLSID rclsid, REFIID riid, LPVOID * ppvObj) {     HRESULT hr = E_OUTOFMEMORY;     *ppvObj = NULL;     CClassFactory *pClassFactory = new CClassFactory(rclsid); //类工厂     if (pClassFactory != NULL)   {         hr = pClassFactory->QueryInterface(riid, ppvObj);         pClassFactory->Release();     }     return hr; }

//②----------------

CFactory::CreateInstance(.....)

{ 　　........... 　　CObject *pObject = new CObject; //组件对象 　　pObject->QueryInterface(IID_IUnknown, (void**)&pUnk); 　　pObject->Release(); 　　........... }

 

实例：

CComPtr<IAVIer> m_piAVIer;

m_piAVIer.CoCreateInstance(L"AVI.AVIer");

 

2、通过LoadLibrary和DllGetClassObject创建组件对象（组件未注册)

CComPtr<IAVIer> m_piAVIer;

typedef int (WINAPI *DllGetClassObjectPtr)(REFCLSID, REFIID, LPVOID*);

HMODULE hModule = LoadLibrary(dll文件路径);

//得到DllGetClassObject函数地址

DllGetClassObjectPtr ProcPtr = (DllGetClassObjectPtr)GetProcAddress(hModule, "DllGetClassObject");

CLSID rclsid;

IID riid; ::CLSIDFromString(A2W("{D5A365A3-44F8-47A0-8FCF-062372B1EB83}"), &rclsid);//类ID ::IIDFromString(A2W("{BE136856-CBEA-4079-A02B-BBC7A382BDB3}"), &riid);//接口ID

IClassFactory *pICF = NULL;//类工厂接口指针

ProcPtr(rclsid, IID_IClassFactory, (void**)(&pICF));//获取类工厂接口指针

//以上相当于①

pICF->CreateInstance(NULL, riid, (void**)&m_piAVIer);//创建COM对象

//以上相当于②

pICF->Release();

 

备注:

AVIer.rgs文件

HKCR

{  Avi.AVIer.1 = s 'AVIer Class'  {   CLSID = s '{D5A365A3-44F8-47A0-8FCF-062372B1EB83}'  }  Avi.AVIer = s 'AVIer Class'  {   CLSID = s '{D5A365A3-44F8-47A0-8FCF-062372B1EB83}'   CurVer = s 'Avi.AVIer.1'  }  NoRemove CLSID  {   ForceRemove {D5A365A3-44F8-47A0-8FCF-062372B1EB83} = s 'AVIer Class'   {    ProgID = s 'Avi.AVIer.1'    VersionIndependentProgID = s 'Avi.AVIer'    ForceRemove 'Programmable'    InprocServer32 = s '%MODULE%'    {     val ThreadingModel = s 'Both'    }    'TypeLib' = s '{59AE79C3-3AC6-42E1-ABED-10B363EDAA4C}'   }  } }

avi.idl文件

 [

  object,   uuid(BE136856-CBEA-4079-A02B-BBC7A382BDB3),//接口ID   dual,   helpstring("IAVIer Interface"),   pointer_default(unique)  ]

 

library AVILib

{  importlib("stdole32.tlb");  importlib("stdole2.tlb");

 [

  uuid(D5A365A3-44F8-47A0-8FCF-062372B1EB83),//类ID   helpstring("AVIer Class")  ]  coclass AVIer  {   [default] interface IAVIer;//类ID  }; };