使DLL COM可访问

#include <unknwn.h>

class __declspec(dllexport) MyComObject : public IUnknown
{
public:
    // 实现 IUnknown 接口
    STDMETHODIMP QueryInterface(REFIID riid, void **ppvObject);
    STDMETHODIMP_(ULONG) AddRef();
    STDMETHODIMP_(ULONG) Release();

    // 添加自定义方法
    HRESULT MyMethod();
};

#include "MyComObject.h"

extern "C" __declspec(dllexport) HRESULT CreateMyComObject(IUnknown **ppUnknown)
{
    MyComObject *pMyComObject = new MyComObject();
    if (!pMyComObject)
    {
        return E_OUTOFMEMORY;
    }

    *ppUnknown = static_cast<IUnknown *>(pMyComObject);
    return S_OK;
}

#include <comdef.h>

HRESULT hr = CoInitialize(NULL);
if (FAILED(hr))
{
    // 处理错误
}

HMODULE hModule = LoadLibrary(TEXT("MyComObject.dll"));
if (!hModule)
{
    // 处理错误
}

typedef HRESULT (__stdcall *PFNCREATEMYCOMOBJECT)(IUnknown **ppUnknown);
PFNCREATEMYCOMOBJECT pfnCreateMyComObject = (PFNCREATEMYCOMOBJECT)GetProcAddress(hModule, "CreateMyComObject");
if (!pfnCreateMyComObject)
{
    // 处理错误
}

IUnknown *pUnknown;
hr = pfnCreateMyComObject(&pUnknown);
if (FAILED(hr))
{
    // 处理错误
}

MyComObject *pMyComObject;
hr = pUnknown->QueryInterface(__uuidof(MyComObject), (void **)&pMyComObject);
if (FAILED(hr))
{
    // 处理错误
}

hr = pMyComObject->MyMethod();
if (FAILED(hr))
{
    // 处理错误
}

pMyComObject->Release();
pUnknown->Release();

FreeLibrary(hModule);
CoUninitialize();