动态导入com dll

问题描述

这是我的代码

Hi,

Here is my code

#import "sample.dll" //This is com dll

using namespace SampleLib; // This is in the dll

main()
{
SampleLib::ISampleLibPtr m_objDll; //The variable ISampleLibPtr is typedef 

m_objDll.CreateInstance("PROG_ID");

m_objDll->create();
}

上面的代码可以正常工作.
我在这里在代码本身中导入dll.
但是我的情况是，有许多实现相同接口的不同版本的com dll.因此，基于给定的版本，我必须选择相关的com dll并进行导入，然后我必须调用create接口.

有人可以帮忙吗?

The above code work fines.
Here i am importing the dll in the code itself.
But i case is , There are many com dll with different version implementing the same interface. So based on the given version i have to select the related com dll and have to import and then i have to call the create interface.

Can any one help on this?

推荐答案

CoInitialize(NULL); // Should be called somethere before  in thread
HMODULE hDll = LoadLibrary(_T("Your_Dll.dll")); // You can also pecify the path - full or relative
if (hDll)
{
	typedef HRESULT (WINAPI * pfnDLLGetClassObject)(REFCLSID rclsid, REFIID riid, LPVOID* ppv);
	// DllGetClassObject function should be imported for COM library
	pfnDLLGetClassObject fnDLLGetClassObject = (pfnDLLGetClassObject)GetProcAddress(hDll,"DllGetClassObject");
	const CLSID _MyObjectCLSID = CLSID_MyObjectInDll; // Your COM Object CLSID in that DLL
	const IID _MyObjectInterfaceIID = IID_IMyObject; // Your COM object interface
	// You can use __uuidof operator in 2 strings above
	IClassFactory * pFactory;
	// Here we obtaining the Class Factory for your object
	hr = fnDLLGetClassObject(_MyObjectCLSID,IID_IClassFactory,(void**)&pFactory);
	IMyObject * pMyObjectInterface;
	hr = pFactory->CreateInstance(NULL,_MyObjectInterfaceIID,(void**)&pMyObjectInterface);
	pFactory->Release();
	// .....
	// If Object no needed
	pMyObjectInterface->Release();
	// If Dll no needed
	FreeLibrary(hDll);
}
CoUninitialize(); // Shutdown COM for current thread

问候，
Maxim.

Regards,
Maxim.

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