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在编写组件程序时，经常会使用CoCreateInstance直接取COM组件的接口，非常方便，那CoCreateInstance到底干了些什么事呢？1、CoCreateInstance取COM组件的接口的基本流程

//参数：rclsid = 组件CLSID
//参数：riid = 接口ID
WINOLEAPI   CoCreateInstance(REFCLSID rclsid, LPUNKNOWN pUnkOuter, DWORD dwClsContext, REFIID riid, LPVOID FAR* ppICOMInterface)
{//根据组件的CLSID从注册表中取Dll的地址,并加载char        pszCOMDllPath;SHGetValue(HKEY_CLASSES_ROOT, "CLSID+rclsid\InprocServer32", "默认", pszCOMDllPath);LoadLibrary(pszCOMDllPath);//调用DllGetClassObject,创建IID_IClassFactory总接口IClassFactory* pIFactory;DllGetClassObject(rclsid, IID_IClassFactory, &pIFactory);{IClassFactory* pITotalFactory = new IClassFactory;pITotalFactory->QueryInterface(IID_IClassFactory, &pIFactory);}//调用CreateInstance创建COM总接口对象pIFactory->CreateInstance(pUnkOuter, riid, ppICOMInterface);{ICOMInterface* pITotalCOMInterface = new ITotalCOMInterface;//根据接口IID取指定接口对象pITotalCOMInterface->QueryInterface(riid, ppICOMInterface);}
}