webBrowser1.Document.Window.Frames[0].Document”引发了“System.UnauthorizedAccessException”类型的异常 System.Windows.Forms.HtmlDocument {System.UnauthorizedAccessException} 

{"拒绝访问。 (异常来自 HRESULT:0x80070005 (E_ACCESSDENIED))"} System.SystemException {System.UnauthorizedAccessException}

最近这个跨域的安全问题很困扰，搞了好久，终于在朋友的帮助下找到了一个C++的方法HtmlWindowToHtmlWebBrowser

CComPtr<IWebBrowser2> CTimerSerachDlg::HtmlWindowToHtmlWebBrowser(CComPtr<IHTMLWindow2> spWindow)
{     
    ATLASSERT(spWindow != NULL);     
    CComQIPtr<IServiceProvider>  spServiceProvider = spWindow;     
    if (spServiceProvider == NULL)     
    {          
        return CComPtr<IWebBrowser2>();     
    }     
    CComPtr<IWebBrowser2> spWebBrws;     
    HRESULT hRes = spServiceProvider->QueryService(IID_IWebBrowserApp, IID_IWebBrowser2, (void**)&spWebBrws);     
    if (hRes != S_OK)     
    {          
        return CComPtr<IWebBrowser2>();     
    }     
    return spWebBrws;
}

// Converts a IHTMLWindow2 object to a IHTMLDocument2. Returns NULL in case of failure.
// It takes into account accessing the DOM across frames loaded from different domains.
CComPtr<IHTMLDocument2> CTimerSerachDlg::HtmlWindowToHtmlDocument(CComPtr<IHTMLWindow2> spWindow)
{     
    ATLASSERT(spWindow != NULL);     
    CComPtr<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.     
    CComPtr<IWebBrowser2>  spBrws = HtmlWindowToHtmlWebBrowser(spWindow);     
    if (spBrws == NULL)     
    {         
        return CComPtr<IHTMLDocument2>();     
    }     
    // Get the document object from the IWebBrowser2 object.     
    CComPtr<IDispatch> spDisp;     hRes = spBrws->get_Document(&spDisp);    
    spDocument = spDisp;     
    return spDocument;
}

在后来找到了作者的Blog，但是国内屏蔽了blogspot,直接不能够访问。

然后发现了作者的另外一篇文章：http://codecentrix.blogspot.com/2008/02/when-ihtmlwindow2document-throws.html

C# 跨域访问iframe的办法：http://www.codecentrix.com/blog/wnd2doc_csharp/GetDocumentFromWindowCsharp.zip

IHTMLWindow2 htmlWindow = (IHTMLWindow2)(((HTMLDocumentClass)(webBrowser1.Document.DomDocument)).frames.item(ref index));
label1.Text = CodecentrixSample.CrossFrameIE.GetDocumentFromWindow(htmlWindow).activeElement.innerHTML;

取到结果，开心。嘎嘎。