How to get the HWND and hook into the WndProc of a WPF application

I've written a quick sample which hooks into the WM_ messages and displays them real-time. It looks like this:



This is the code that does the work:

private void Window1_Loaded(object sender, RoutedEventArgs e)
{
    // do this to get the HWND and set up the window hook
    WindowInteropHelper helper = new WindowInteropHelper(this);
    HwndSource.FromHwnd(helper.Handle).AddHook(HwndSourceHookHandler);
}

private IntPtr HwndSourceHookHandler(IntPtr hwnd, int msg, IntPtr wParam, 
    IntPtr lParam, ref bool handled)
{
    // this is the window hook handler
}

Download sample app with source code