如何在 MFC 编程中使用 GetDHtmlDocument()?

2022-01-12 00:00:00 focus c++ mfc dhtml hresult

我正在尝试使用

HRESULTGetDHtmlDocument(IHTMLDocument2**pphtmlDoc);

HRESULT GetDHtmlDocument(IHTMLDocument2 **pphtmlDoc);

MFC 编程中的函数.

function in MFC programming.

基本上，我试图在给定不同配置(加载输入)的 HTML 视图对话框应用程序(C++ w/MFC)中呈现 GUI.

Basically, I am trying to render GUI in a HTML View Dialog application (C++ w/ MFC) given different configuration (loading input).

所以我将以下代码放入 OnInitDialog() 函数中.

So I put following code in a OnInitDialog() function.

BOOL CSampleProgramDlg::OnInitDialog()
{
    CDHtmlDialog::OnInitDialog();

    ASSERT((IDM_ABOUTBOX & 0xFFF0) == IDM_ABOUTBOX);
    ASSERT(IDM_ABOUTBOX < 0xF000);

    CMenu* pSysMenu = GetSystemMenu(FALSE);
    if (pSysMenu != NULL)
    {
        BOOL bNameValid;
        CString strAboutMenu;
        bNameValid = strAboutMenu.LoadString(IDS_ABOUTBOX);
        ASSERT(bNameValid);
        if (!strAboutMenu.IsEmpty())
        {
            pSysMenu->AppendMenu(MF_SEPARATOR);
            pSysMenu->AppendMenu(MF_STRING, IDM_ABOUTBOX, strAboutMenu);
        }
    }

    SetIcon(m_hIcon, TRUE); 
    SetIcon(m_hIcon, FALSE);

    // My code starts from here....
    HRESULT hr = S_OK;
    IHTMLDocument2 *pphtmlDoc;

    //MessageBox(_T("If I let this MessageBox to pop-up, the code works fine."));

    hr = GetDHtmlDocument(&pphtmlDoc);

    IHTMLElement *e;
    hr = GetElement(_T("someElement"), &e);

    if (SUCCEEDED(hr))
        e->put_innerHTML(_T("<h1>someLoadingInputWillGoHereLater</h1>"));

    //My code ends here.....

    return TRUE;
}

正如我在上面的代码中注释掉的，如果我让 Messagebox 弹出 ID="someElement" 的元素将打印出 "someLoadingInputWillGoHereLater".

As I commented out in the above code, if I let the Messagebox to pop-up the element with ID="someElement" will print out "someLoadingInputWillGoHereLater".

但如果我注释掉消息框，GetDHtmlDocument() 会返回E_NOINTERFACE"HRESULT，这会使代码无法工作.

But if I comment out the Messagebox, GetDHtmlDocument() returns "E_NOINTERFACE" HRESULT, and it makes the code not working.

我只能猜测它可能是焦点"问题.不过，我无法弄清楚确切的原因.

I can only guess it maybe "focus" issue. I cannot figure out the exact cause, though.

所以我请求你的帮助.=(

So I ask for your help. =(

推荐答案

您对 GetDHtmlDocument() 和 GetElement() 的调用将返回 E_NOINTERFACE.

Your calling to GetDHtmlDocument() and GetElement() will return E_NOINTERFACE.

据我所知，当您在 CDHtmlDialog::OnInitDialog() 中执行时，不总是保证完全加载 html 文档.

According to my knowledge, you are not always guaranteed to have html document completely loaded when you're performing in CDHtmlDialog::OnInitDialog().

相反，您应该在 CSampleProgramDlg 中覆盖 CDHtmlDialog::OnDocumentComplete().这是一个回调函数，将在加载文档时调用.然后您就可以评估文档了.

Instead, you should override CDHtmlDialog::OnDocumentComplete() in CSampleProgramDlg. It's a callback function that'll be called when document is loaded. You can assess the document then.

void CSampleProgramDlg::OnDocumentComplete(
   LPDISPATCH pDisp,
   LPCTSTR szUrl 
)
{
    // You can get the document and elements here safely
}

您对 MessageBox() 的调用可能会以某种方式触发文档提前加载.虽然我不是 100% 确定.

Your calling to MessageBox() may somehow trigger the document to be loaded in advance. Though I'm not 100% sure for it.

希望对您有所帮助.

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