c++ - CoCreateInstance 返回 E_INVALIDARG

Question

我在这里尝试做的只是创建一个接口(interface)的实例。真的应该这么简单。一直在关注任何在线资料，阅读我能找到但终生无法解决这个问题的资料。

它归结为从 CoCreateInstance 返回的 HRESULT 是 E_INVALIDARG。我已尽可能多地更改参数以尝试使其正常工作，但仍然无法正常工作。所以请看一眼，希望有人能指出一些我忽略的简单问题。

//Instantiate the sink class and hold a pointer to it.
    m_pSink = new CSink();

    HRESULT hr = CoInitialize(NULL);

    //Get a pointer to sinks IUnknown, no AddRef. CMySink implements only
    //dispinterface and the IUnknown and IDispatch pointers will be same.
    LPUNKNOWN pUnkSink = m_pSink->GetIDispatch(FALSE); 

    CLSID clsidInterface;
    hr = CLSIDFromProgID(L"Automation.AutomationInterface", &clsidInterface);

    ICALib::IAutomationInterface *p_Interface = NULL;
    hr = CoCreateInstance(clsidInterface, NULL, CLSCTX_LOCAL_SERVER, ICALib::IID_IAutomationInterface, (void**)p_Interface);

    if (hr != S_OK) // Show a message box if the Instance of the interface is not created and do not create the object.
    {
        CMessageBox(CMessageBox::WARNING_OK).Show(IDS_WARNING_BADLICENSE);
        m_failedToCreate = TRUE;
        this->~CMainClass();
        return;
    }

    //Establish a connection between source and sink.
    //m_pUnkSrc is IUnknown of server obtained by CoCreateInstance().
    //m_dwCookie is a cookie identifying the connection, and is needed to terminate the connection.
    BOOL result = AfxConnectionAdvise(p_Interface, m_pSink->GetGUID(), pUnkSink, FALSE, &m_dwCookie);

(由于法律责任，此代码中未显示实际名称)

Answer 1

您需要获取 p_Interface 的地址并将其传递给 CoCreateInstance。事实上，您只是为最后一个参数传递了一个 NULL 指针。