Custom System Tray for a Custom Shell

Question

I'm creating a custom shell for Windows 7 / 8. How do I create a custom tray for my shell ? I'm aware that the tray window has the class name "Shell_TrayWnd". I tried creating it on my own and posted "TaskbarCreated" message using PostMessage but I'm not getting "WM_COPYDATA" message in my Tray WndProc. I'm missing out on something? Need help.

The code is as follows:

static LRESULT CALLBACK tray_proc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) 
{
   if (uMsg == WM_COPYDATA)
   {
        COPYDATASTRUCT *cpdata = (COPYDATASTRUCT*)lParam;
   }
   return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

int init_tray(void) 
{
    WNDCLASS wc;
    memset(&wc, 0, sizeof(wc));
    wc.lpfnWndProc = tray_proc;
    wc.hInstance = GetModuleHandle(NULL);
    wc.lpszClassName = TEXT("Shell_TrayWnd");

    if (!RegisterClass(&wc)) 
    {
        return 0;
    }

tray_window = CreateWindowEx(
    WS_EX_TOOLWINDOW,
    wc.lpszClassName,
    NULL,
    WS_POPUP,
    0, 0, 0, 0,
    NULL, NULL,
    wc.hInstance,
    NULL);

if (!tray_window)
    return 0;

/* let running apps know that a new tray is around */
PostMessage(HWND_BROADCAST, RegisterWindowMessage(TEXT("TaskbarCreated")), 0, 0);

return 1;
}

Answer 1

Got it working!

SendNotifyMessage(HWND_BROADCAST, RegisterWindowMessage("TaskbarCreated"), 0, 0);

This message is the key. Without this, the Tray WndProc will not get data.