Introduction

This article will showcase the technique to host WPF content in an MFC-based application. The main usage of this implementation is to enhance the graphical appearance of conventional Win32/MFC-based applications. The demo program that comes along with this article will host an animated WPF clock in an MFC dialog program.

Development Tools & Library

• MS Visual Studio 2005 or above
• MS .NET Framework 3.0 or above (download)

• Windows Vista
• Windows XP SP2
• Windows Server 2003 SP1

If you are a C++ developer and want to use WPF as an add-on to enhance the graphical UI of your existing Win32/MFC applications, this article is written for you. To get the most out from this article, you should be familiar with VC++/CLi, MFC, XAML, and C#. But, if you don't know C# or XAML, you can still proceed just by referencing the generated DLL and make use of it in your MFC application.

WPF stands for Windows Presentation Foundation. It's a subsystem of Microsoft .NET Framework 3.0. It allows developers to productively create visually appealing applications and improve user experience. The deployment of WPF enables richer control, design, and development of the visual aspects of Windows programs. It aims to unify a host of application services: user interface, 2D and 3D drawing, fixed and adaptive documents, advanced typography, vector graphics, animation, data binding, audio, and video. WPF also provides a consistent programming model for building applications and provides a clear separation between the UI and the business logic.

Those are all the basic ground rules you should know; it'd time to get to the code. Here, I will show you WPF content created in XAML and C#, and the generated DLL will be referenced in VC++.

The idea is to create a simple Date & Time setting tool with the animated clock part implemented as a WPF content. The rest of the program still will be coded in MFC.

Adding WPF-Related Code to an MFC Application

For your information, the gcnew keyword is used to create an instance of managed type; this will create the instance on the garbage collected heap. All memory allocated by gcnew will be managed automatically by the garbage collector and developers will not need to worry about freeing them up.

To host WPF content, the key is on the System::Windows::Interop::HwndSource class. This class will take care of wrapping the WPF content in a Win32 window, so that the WPF content can be incorporated into your user interface (UI) as a child window. Communication with the WPF content object is done by using the reference stored in the static fields. They're declared as static to prevent them from being inadvertently garbage collected.

• Class, window, and styles
• Initial position of the window
• Initial size of the window
• The parent window

HWND GetHwnd(HWND parent, int x, int y, int width, int height)
{
   System::Windows::Interop::HwndSourceParameters^ sourceParams =
      gcnew System::Windows::Interop::HwndSourceParameters
      ("MFCWPFApp");
   sourceParams->PositionX    = x;
   sourceParams->PositionY    = y;
   sourceParams->Height       = height;
   sourceParams->Width        = width;
   sourceParams->ParentWindow = IntPtr(parent);
   sourceParams->WindowStyle  = WS_VISIBLE | WS_CHILD;
   Globals::gHwndSource =
      gcnew System::Windows::Interop::HwndSource(*sourceParams);

   DateTime tm = DateTime::Now;
   Globals::gwcClock = gcnew WPFControls::AnimClock();
   Globals::gwcClock->ChangeDateTime(tm.Year,tm.Month,tm.Day,
                                     tm.Hour,tm.Minute,tm.Second);
   FrameworkElement^ myPage = Globals::gwcClock;

   Globals::gHwndSource->RootVisual = myPage;
   return (HWND) Globals::gHwndSource->Handle.ToPointer();
}

void RefreshWPFControl()
{
   FrameworkElement^ page;
   DateTime tm = DateTime::Now;

   Globals::gwcClock->ChangeDateTime(tm.Year,tm.Month,tm.Day,
                                     tm.Hour,tm.Minute,tm.Second);
   page = Globals::gwcClock;

   Globals::gHwndSource->RootVisual = page;

   return;
}