Qt Zebra扫码枪的命令发送和接收com组件的事件

如题，zebra官网给出的扫码枪SDK示例是基于MFC的，自己用的是QT，加大了开发难度（悔不当初用MFC），同时也对com组件不熟悉，导致折腾了好几天才搞定。也不知道这么做能不能满足QT跨平台的初衷，Windows是能用的，给大家参考一下。

1、下面是代码，命令发送这部分很容易解决，稍微改下就行，主要是接收com组件的事件，我这边采用了回调函数的方式接收信息。

private:
    DWORD m_dwRefCount;
    Callback  //自己定义的回调函数
    void * user;
public:    
    void SetCallbackFunc(CallbackGetScannerData cbk, void* user)
    {
        this->cbkGetData = cbk;
        this->user = user;
    }
    
    CEventSink() { m_dwRefCount = 0; }
    virtual ~CEventSink(void) {}
    
    STDMETHODIMP GetTypeInfoCount(UINT *pctinfo) { return E_NOTIMPL; }
    STDMETHODIMP GetTypeInfo(UINT iTInfo, LCID lcid, ITypeInfo **ppTInfo) { return E_NOTIMPL; }
    STDMETHODIMP GetIDsOfNames(REFIID riid, LPOLESTR *rgszNames, UINT cNames, LCID lcid, DISPID *rgDispId) { return E_NOTIMPL; }
    
    STDMETHODIMP Invoke(DISPID dispIdMember, REFIID riid, LCID lcid, WORD wFlags, DISPPARAMS *pDispParams, VARIANT *pVarResult, EXCEPINFO *pExcepInfo, UINT *puArgErr)
    {
        LONG *lValue = pVarResult->plVal;
        switch (dispIdMember)
        {
        case 3:      //能获取到扫描枪扫的条码信息
        {
            VARIANT varlValue;
            VARIANT varlValue1;
            short lValue = 0;
            BSTR lValue1;
            varlValue = (pDispParams->rgvarg)[1];
            varlValue1 = (pDispParams->rgvarg)[0];
            //varlValue1.pbstrVal
            lValue = V_I2(&varlValue);
            lValue1 = SysAllocString(*(varlValue1.pbstrVal));
            if(cbkGetData)
                //放自己定义的回调函数
            break;
        }
        default:
            break;
        }
        //printf(" ---------the result %d\n", *lValue);
        //OnReceiver(lValue);
        return S_OK;
    }
    STDMETHOD(QueryInterface)(REFIID iid, LPVOID* ppv)
    {
        if ((iid == __uuidof(_ICoreScannerEvents)) || //(iid == __uuidof(IMarshal)) ||
            (iid == __uuidof(IDispatch)) ||
            (iid == __uuidof(IUnknown)))
        {
            m_dwRefCount++;
            *ppv = this;
        }
        else
        {
            *ppv = NULL;
            return E_NOINTERFACE;
        }
        return S_OK;
    }
    STDMETHOD_(ULONG, AddRef)()
    {
        return InterlockedIncrement(&m_dwRefCount);
    }
    STDMETHOD_(ULONG, Release)()
    {
        InterlockedDecrement(&m_dwRefCount);
        if (m_dwRefCount != 0)
            return m_dwRefCount;
        delete this;
        return 0;
    }
};

2、下面是调用的这个类的代码

 if(ScannerInterface)
    {
        HRESULT hr = S_FALSE;
        //Create the Scanner COM object
        IConnectionPointContainer *pCPC;
        hr = ScannerInterface->QueryInterface(IID_IConnectionPointContainer, (void **)&pCPC);
        if (!SUCCEEDED(hr))
        {
            return -1;
        }

        //获取连接点
        hr = pCPC->FindConnectionPoint(DIID__ICoreScannerEvents, &pCP);
        if (!SUCCEEDED(hr))
        {
            return -1;
        }
        pCPC->Release();

        IUnknown *pSinkUnk;
        ScannerEventSink = new CEventSink();
        ScannerEventSink->SetCallbackFunc(//自定义的回调函数, user);

        hr = ScannerEventSink->QueryInterface(DIID__ICoreScannerEvents, (void **)&pSinkUnk);
        hr = pCP->Advise(pSinkUnk, &dwAdvise);//注册其接收接口指针
        if (!SUCCEEDED(hr))
        {
            return -1;
        }
    }