WPF Hook Message

IntPtr hwnd = new WindowInteropHelper(this).Handle;
HwndSource.FromHwnd(hwnd).AddHook(new HwndSourceHook(WndProc));

private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
{
    if (msg == WM_PAINT)
    {
        //Do some extra actions.
    }
    return IntPtr.Zero;
}