Marc Gregoire’s Blog

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You can also browse the above site to learn all the new features of IE9, especially its focus on speed and standard compliancy 🙂

Microsoft has released the release candidate of Internet Explorer 9.
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Today Microsoft released a public beta of Internet Explorer 9. The new version is much better standard compliant and support such standards as HTML5, CSS3 and SVG2. It scores a nice 95/100 on the Acid3 test. I just installed it myself and I’m impressed with how much faster it works compared to IE8. You can read a full review here.
Download it here.

In my previous blog entry titled “How To Use the Microsoft WebBrowser Control to Render HTML from Memory” I described a method how you could use the Microsoft WebBrowser Control to display HTML from memory. One commenter said that it was not possible to navigate to an anchor in the body onload handler. I did some research and it seems all navigation within the rendered page is not working. For example, the following piece of HTML code will not work correctly:

<a href="#n25">Jump to anchor n25</a>
<a name="n25">25</a>

It took me a while to find a workaround, so that’s why I’m posting it now for other people to use. Basically, we cannot use the standard navigation techniques. I tried several possible workaround and the only one that I got working properly is by manually scrolling the window until the requested anchor is visible. It sounds complicated, but it really works pretty nicely. I wrote this little wrapper function to do all the hard work.

void CMyDlg::ScrollToAnchor(const wchar_t* anchor)
{
    IDispatch* pHtmlDoc = m_explorer.get_Document();
    if (!pHtmlDoc)
        return;
    CComPtr<IHTMLDocument2> doc2;
    doc2.Attach((IHTMLDocument2*)pHtmlDoc);
    if (doc2)
    {
        CComPtr<IHTMLElementCollection> anchors;
        HRESULT hr = doc2->get_anchors(&anchors);
        if (SUCCEEDED(hr) && anchors)
        {
            _variant_t index = 0;
            _variant_t str = anchor;
            IDispatch *pdisp;
            hr = anchors->item(str, index, &pdisp);
            if (SUCCEEDED(hr) && pdisp)
            {
                CComPtr<IHTMLElement> el;
                hr = pdisp->QueryInterface(IID_IHTMLElement, (void**)&el);
                if (SUCCEEDED(hr) && el)
                {
                    long yTotal = 0;
                    while (1)
                    {
                        long y;
                        el->get_offsetTop(&y);
                        yTotal += y;
                        CComPtr<IHTMLElement> el2;
                        hr = el->get_offsetParent(&el2);
                        if (SUCCEEDED(hr) && el2)
                            el = el2;
                        else
                            break;
                    }
                    CComPtr<IHTMLWindow2> wnd;
                    hr = doc2->get_parentWindow(&wnd);
                    if (SUCCEEDED(hr) && wnd)
                        wnd->scrollTo(0, yTotal);
                }
            }
        }
    }
}

What it does is it gets a pointer to the document. Then gets a list of all the anchors in the document and get the anchor with the given name out of that list. Once we have the target element, we calculate the offset from the top of the document. This is done in a while loop, because the target anchor could be inside another element like a div or a table. After calculating the offset, we get a pointer to the HTML window and call the scrollTo function to make it scroll to the anchor position.

Now the only thing you need to do is to render your HTML using the method in my previous blog entry and then call this new ScrollToAnchor function with the name of the anchor to which you want to scroll.

Microsoft has a WebBrowser control that is actually an Internet Explorer control that you can use to display HTML in your own applications. More information about this WebBrowser control can be found on MSDN. By using this control it’s very easy to display online or offline webpages. However, it’s not immediately obvious how to make it display HTML that you might have in a memory buffer. Of course, one solution is to write the HTML to a temporary file and then load that file using the WebBrowser control, but obviously there is a better way for doing this which I will explain below.

The first thing you have to do is to add the WebBrowser control to your dialog. So, in Visual Studio, open the resource editor and then open the dialog onto which you want to put the WebBrowser control. Once the dialog is opened in the resource editor, right click on an empty space on the dialog and select “Insert ActiveX Control…”. This will open a new window in which you can select “Microsoft Web Browser” and then click OK. Visual Studio will automatically create a wrapper class for this ActiveX control which will probably be called explorer.h and explorer.cpp while the wrapper class will most likely be called CExplorer.

Now, right click the WebBrowser control on your dialog and select “Add Variable”. Make a variable with category set to “Control” and with the variable type set to the wrapper class “CExplorer” and hit OK.

Now we can start writing code. The first thing required is to load up some basic document; I use about:blank. Do this in your OnInitDialog handler as follows.

COleVariant loc(L"about:blank");
m_explorer.Navigate2(loc, NULL, NULL, NULL, NULL); 

The above is very important. If you don’t load an initial document, the WebBrowser control will not render any HTML that you try to push to it. This also means that before you can start writing HTML from memory in the WebBrowser control, you have to wait until the initial document has been fully loaded. This can be done with the “DocumentComplete” event. In the dialog editor, right the WebBrowser control and click on “Add Event Handler…”. Select “DocumentComplete” as message type, select the appropriate class and click “Add and Edit”. You can use that handler to change a boolean variable in your code to mark whether the document has been fully loaded. When it is fully loaded you can start writing HTML from memory to it.

Once that is finished, you can add the following helper function:

#include <MsHTML.h>
void CMyDlg::WriteHTML(const wchar_t* html)
{
	IDispatch* pHtmlDoc = m_explorer.get_Document();
	if (!pHtmlDoc)
		return;
	CComPtr<IHTMLDocument2> doc2;
	doc2.Attach((IHTMLDocument2*)pHtmlDoc);
	if (!doc2)
		return;
	 // Creates a new one-dimensional array
	SAFEARRAY* psaStrings = SafeArrayCreateVector(VT_VARIANT, 0, 1);
	if (!psaStrings)
		return;
	BSTR bstr = SysAllocString(html);
	if (bstr)
	{
		VARIANT* param;
		HRESULT hr = SafeArrayAccessData(psaStrings, (LPVOID*)&param);
		if (SUCCEEDED(hr))
		{
			param->vt = VT_BSTR;
			param->bstrVal = bstr;
			hr = SafeArrayUnaccessData(psaStrings);
			if (SUCCEEDED(hr))
			{
				doc2->write(psaStrings);
				doc2->close();
			}
		}
	}
	// SafeArrayDestroy calls SysFreeString for each BSTR!
	if (psaStrings)
		SafeArrayDestroy(psaStrings);
}

With the above function, it’s very easy to dynamically create and display HTML from memory. For example:

WriteHTML(L"<html><body><h1>My Header</h1><p>Some text below the header</p></body></html>");

Note that the above code is expecting a Unicode build. If you don’t use Unicode, you need to change the wchar_t types and you need to change the way how you allocate the BSTR variable.

That’s it. Pretty easy if you know how to do it, but it took me some time to figure it out.

[ Update: Fixed some typos and added mshtml.h reference. ]

[ Update 2: Added a call to “doc2->close();” after “doc2->write()” and added code to check the result of the doc2.Attach() call. ]

It seems Microsoft will not release a Windows 7 E for the European Union after all. Windows 7 E was planned for the EU to be a Windows 7 version without Internet Explorer. Now, Microsoft will implement a ballot screen that will be shown the first time a user starts Internet Explorer. That ballot screen gives the user the option to select a different browser like Firefox, Safari, Chrome, Opera and so on.

After installation of Internet Explorer 8, some wizard in Visual Studio 2005 and 2008 might give a script error. The following wizards might be affected:

• Add Function
• Add Variable
• Smart Device – New Project Creation
• Smart Device – Add Class

Get the workaround from the Visual C++ Team Blog.