WebBrowser获取页面总高度

case DISPID_DOCUMENTCOMPLETE:
        {
#pragma region 获取页面总高度

            HRESULT hr;
            IDispatch *pdisp;
            hr = m_pWebBrowser2->get_Document(&pdisp);
            if(pdisp == NULL) break; //if NULL, we failed 

            // 获得Html文档指针 
            IHTMLDocument2 *pDocument = NULL;
            hr = pdisp->QueryInterface(IID_IHTMLDocument2, (void**)&pDocument);
            if (pDocument == NULL) break;

            IHTMLElement *pBody = NULL;
            hr = pDocument->get_body(&pBody);
            if (pBody == NULL) break;

            IHTMLTextContainer *pCont = NULL;
            pBody->QueryInterface(IID_IHTMLTextContainer, (LPVOID*)(&pCont));
            if(pCont == NULL) break;

            // 获得页面总高度 
            long scroll_height = -1;
            if (FAILED(pCont->get_scrollHeight(&scroll_height)))
                break;

            pBody->Release();
            pCont->Release();
            pDocument->Release();
            pdisp->Release();

            if (scroll_height != -1)
                m_dwHtmlHeight = scroll_height;

            if (NULL != m_pManager)
                m_pManager->SendNotify(this, _T("document_complete"), scroll_height);

#pragma endregion
　　　　}