Marc Gregoire’s Blog

The Windows Phone Application Platform was revealed at MIX 2010. If you couldn’t make it to Las Vegas to attend MIX, you can find the keynotes and sessions here. They explain in great details the Windows Phone 7 Series and how to develop applications for it.

The WP7S developer platform contains 2 frameworks:

• Silverlight: to make rich interactive applications
• XNA: to make complex 2D/3D games

Code is written in C#.

Everyone can start writing applications for the new phone platform. You only need to download 1 free package. This packages contains:

• Visual Studio 2010 Express for Windows Phone CTP
• Windows Phone Emulator CTP
• Silverlight for Windows Phone CTP
• XNA 4.0 Game Studio CTP

Download the package to get started. Only Windows Vista and Windows 7 are officially supported to run the tools. Note that the tools are currently in CTP state so they are not yet final. If you want to use Expression Blend you have to download it separately.

More information can be found on the Windows Phone 7 Series Developer Site, where you can also find developer guides, more detailed information, Windows Marketplace submission guidelines, forums, a few code samples etc…

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. ]

This is a message to everyone who is running an older version of Windows. There are a few End of Life Support dates coming up, so it’s important to keep that in mind to avoid running unsupported versions of Windows.

Windows 2000 Professional and Windows 2000 Server are approaching 10 years since their launch and both products will go out of support on July 13, 2010.

Windows XP was launched back in 2001. While support for the product will continue, Service Pack 2 will go out of support on July 13, 2010. From that date onwards, Microsoft will no longer support or provide free security updates for Windows XP SP2.  Please install the free Service Pack 3 for Windows XP to have the most secure and supported Windows XP platform.

Finally, Windows Vista with no Service Packs installed will end support on April 13 2010.  Please install the free Service Pack 2 for Windows Vista to have the most secure and supported Windows Vista platform.

The Release Candidate of Visual Studio 2010 has changed the behaviour of RValue references slightly compared to the implementation in the Visual Studio 2010 beta versions. This is because the C++0x standard commitee has changed the RValue reference feature a bit and Visual Studio 2010 RC has incorporated those standard changes. Unfortunately, this might lead to compiler errors when you try to build code that is following the old standard. Let me give an example. Previously using a beta version of Visual Studio 2010 that was using the old C++0x standard, the following code would compile without any problems.

#include <iostream>
using namespace std;

// Increment value by 1 using RValue reference parameter.
int increment(int&& value)
{
   cout << "value = " << value << endl;
   value++;
   return value;
}

int main()
{
   int a = 10;
   int b = 20;

   // Increment a
   int result = increment(a);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment b
   result = increment(b);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment an expression
   result = increment(a + b);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment a literal
   result = increment(3);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;

   return 0;
} 

However, when trying to compile this using the latest release candidate of Visual Studio 2010, you will get the following errors:

rvalue_test.cpp(18): error C2664: 'increment' : cannot convert parameter 1 from 'int' to 'int &&'
          You cannot bind an lvalue to an rvalue reference
rvalue_test.cpp(21): error C2664: 'increment' : cannot convert parameter 1 from 'int' to 'int &&'
          You cannot bind an lvalue to an rvalue reference

These are related to the lines that are trying to increment a and b. Incrementing an expression or a literal still works as before. To get rid of those errors, you need to convert the lvalue to an rvalue. You can use the std::move function for this as shown in red below.

#include <iostream>
using namespace std;

// Increment value by 1 using RValue reference parameter.
int increment(int&& value)
{
   cout << "value = " << value << endl;
   value++;
   return value;
}

int main()
{
   int a = 10;
   int b = 20;

   // Increment a
   int result = increment(std::move(a));
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment b
   result = increment(std::move(b));
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment an expression
   result = increment(a + b);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;
   // Increment a literal
   result = increment(3);
   cout << "  a=" << a << ", b=" << b << ", result=" << result << endl;

   return 0;
}

This now compiles without any errors and produces the following output:

value = 10
  a=11, b=20, result=11
value = 20
  a=11, b=21, result=21
value = 32
  a=11, b=21, result=33
value = 3
  a=11, b=21, result=4

Now, it again works as expected