How to register/listen the desktop window to my own WndProc?

Question

I need to get the the mouse messages on the desktop window (GetDesktopWindow()), how can I register my own WndProc so I can listen to those mouse messages?

I thought I could do the following, however, per MSDN, RegisterClass() is for CreateWindow(), etc. As Desktop window has been created, how can I assign my own WndProc to the desktop window so I can listen all mouse messages?

  WCHAR consoleTitle[500];
    GetConsoleTitle( consoleTitle, 500);    
    HWND hwndConsole = FindWindow(NULL, consoleTitle);  
    HINSTANCE hInstance = (HINSTANCE)GetWindowLong(hwndConsole, GWL_HINSTANCE);
    WNDCLASS wc = {0};
    wc.hbrBackground =(HBRUSH)GetStockObject(HOLLOW_BRUSH);
    wc.hCursor = LoadCursor( hInstance, IDC_ARROW );
    wc.hIcon = LoadIcon( hInstance, IDI_APPLICATION );

    // Provide handle from GetDesktopWindow() to WNDCLASS ?!
    wc.hInstance = GetDesktopWindow();
    wc.lpfnWndProc = WndProc;
    wc.lpszClassName = L"Test Window"; 
    wc.style = CS_HREDRAW | CS_VREDRAW;

    if (! RegisterClass( &wc ) )
    {
        // throw exception;
    }
    
    HWND hDesktop;
    RECT rt;

    hDesktop = GetDesktopWindow();
    GetWindowRect(hDesktop, &rt);
    
    //
    // Use CreateWindow() to create the desktop window again?

Thanks.

Answer 1

As I don't know the objective you need to fulfill with this request I cannot be sure, but I'll suggest an alternative anyway:  Raw Input.  It is a great alternative to mouse or keyboard hooking.

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Jose R. MCP

Answer 2

Thanks for the info, look like Raw Input still needs to use WM_* (windows message), e.g. WM_INPUT to get the raw input. So I guess my initial question still apply, but correctly me if I'm wrong.

Also, raw input has a structure called RAWINPUTDEVICE structure, which has usUsagePage and usUsage. Where can I get the usUsagePage/usUsage for the following input devices?

keyboard, mouse and touch?

Basically, I need to capture the input device's (mouse/keyboard/touch) input from a user's computer and display what the mouse's co-ordinate/action, keyboard input and touch point co-ordinate/action on my app.

Their input is not limited to my app's window area, but the overall user's desktop, regardless my app is in the foreground or background.

Thanks.

Answer 3

You could try and use the SetWinEventHook function.

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«_Superman_»
Microsoft MVP (Visual C++)

Polymorphism in C

Answer 4

Yes, you need a window that receives the WM_INPUT message, but the good thing is that you don't need to subclass a foreign window and instead you can simply provide your own window, which simplifies the scenario.

As for the codes, for mouse and keyboard you use usUsagePage = 1, usUsage = 1 or 6 (or was it 6 or 1?  Verify it).  For other input devices, I don't know.  You'll have to look them up or request them from Microsoft, maybe from Microsoft Support (not free).

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Jose R. MCP