Which window has the focus

[C++ Programming]

I have to return the path of the selected file , EITHER in the Desktop or in the Windows Explorer.

I can get the path of the selected file both on the Windows Explorer and the desktop

My problem is that I am unable to find which window has the current focus

1) The user has selected a file on the desktop
2) The user has selected a file in the Windows explorer. ( So this has the focus now )

How do I programatically find that out

I am using the following code

HWND hWndDesktop = GetDesktopHandle(); // Gets the handle of the SyslistView32 window

DWORD dwThread = ::GetWindowThreadProcessId(hWndDesktop, NULL);

GUITHREADINFO gtf ;

gtf.cbSize = sizeof(GUITHREADINFO);

BOOL b = GetGUIThreadInfo(dwThread, &gtf);

if(hWndDesktop == gtf.hwndFocus)
{
// this window currently has the focus
}

But I am getting different handles for hWndDesktop and gtf.hwndFocus .

Please let me know if I am missing something

Thanks
Sujay