利用IHTMLWindow2 的get_document 返回E_ACCESSDENIED 解决方法

获得iframe标签的元素指针

CComPtr<IHTMLElement> spAdIframe = ...

CComQIPtr<IHTMLFrameBase2> spFrameBase2 = spAdIframe;

CComPtr<IHTMLWindow2> spIframeWindow2 = NULL;

hr = spFrameBase2->get_contentWindow(&spIframeWindow2);

由此可得到iframe元素对应的IHTMLWindow2指针，然而如果直接使用IHTMLWindow2::get_document来获取IHTMLDocument2指针的话，经常得到的是E_ACCESSDENIED错误，因为iframe元素经常用于跨域的访问，即iframe内的文档来源src与其parent的src的hostname不同，但可以通过下面的方法绕过webbrowser的安全检查。

CComQIPtr<IHTMLDocument2> HtmlWindowToHtmlDocument(CComQIPtr<IHTMLWindow2> spWindow)

{
ATLASSERT(spWindow != NULL);
 
CComQIPtr<IHTMLDocument2> spDocument;
HRESULT hRes = spWindow->get_document(&spDocument);
 
if ((S_OK == hRes) && (spDocument != NULL))
{
// The html document was properly retrieved.
return spDocument;
}

 
// hRes could be E_ACCESSDENIED that means a security restriction that
// prevents scripting across frames that loads documents from different internet domains.
CComQIPtr<IWebBrowser2> spBrws = HtmlWindowToHtmlWebBrowser(spWindow);
if (spBrws == NULL)
{
return CComQIPtr<IHTMLDocument2>();
}

 
// Get the document object from the IWebBrowser2 object.
CComQIPtr<IDispatch> spDisp;
hRes = spBrws->get_Document(&spDisp);
spDocument = spDisp;
 
return spDocument;

}

 

 

CComQIPtr<IWebBrowser2> HtmlWindowToHtmlWebBrowser(CComQIPtr<IHTMLWindow2> spWindow)

{

    ATLASSERT(spWindow != NULL);

 

    CComQIPtr<IServiceProvider>   spServiceProvider = spWindow;

    if (spServiceProvider == NULL)

    {

        return CComQIPtr<IWebBrowser2>();

    }

 

    CComQIPtr<IWebBrowser2> spWebBrws;

    HRESULT hRes = spServiceProvider->QueryService(IID_IWebBrowserApp, IID_IWebBrowser2, (void**)&spWebBrws);

    if (hRes != S_OK)

    {

        return CComQIPtr<IWebBrowser2>();

    }

 

    return spWebBrws;

}