Add a global Windows hotkey without a running application

Question

I want to create a global hotkey to launch my application even if it's not running (without a background process).

From what I've read, RegisterHotkey requires a process to be running to pick up the hotkey message.

I tried using IShellLink::SetHotkey on a shortcut to the application but it seems really flaky. Despite calling SHChangeNotify, the hotkey won't clear when I set the shortcut's hotkey to none. Is there something I have to do to make the windows shell realize that the shortcut's hotkey has changed?

I think you can actually get this same flaky behavior through the Windows UI by setting the hotkey through the shortcut properties, pressing apply and then changing the hotkey and applying again. The old hotkey will still work.

Any recommendations on how to do this or corrections to my investigation?

score 0 · Answer 1 · answered Jan 25 '14 at 14:31

Try this code:

#define _WIN32_WINNT 0x0400
#pragma comment( lib, "user32.lib" )

#include <windows.h>
#include <stdio.h>

HHOOK hKeyboardHook;

__declspec(dllexport) LRESULT CALLBACK KeyboardEvent (int nCode, WPARAM wParam, LPARAM lParam)
{
    DWORD SHIFT_key=0;
    DWORD CTRL_key=0;
    DWORD ALT_key=0;

    if  ((nCode == HC_ACTION) &&   ((wParam == WM_SYSKEYDOWN) ||  (wParam == WM_KEYDOWN)))      
    {
        KBDLLHOOKSTRUCT hooked_key =    *((KBDLLHOOKSTRUCT*)lParam);
        DWORD dwMsg = 1;
        dwMsg += hooked_key.scanCode << 16;
        dwMsg += hooked_key.flags << 24;
        char lpszKeyName[1024] = {0};
        //lpszKeyName[0] = '[';

        int i = GetKeyNameText(dwMsg,   (lpszKeyName+1),0xFF) + 1;
        //lpszKeyName[i] = ']';

        int key = hooked_key.vkCode;

        SHIFT_key = GetAsyncKeyState(VK_SHIFT);
        CTRL_key = GetAsyncKeyState(VK_CONTROL);
        ALT_key = GetAsyncKeyState(VK_MENU);

        if (key >= 'A' && key <= 'Z')   
        {

            if  (GetAsyncKeyState(VK_SHIFT)>= 0) key +=32;

            if (CTRL_key !=0 && key == 'y' )
            {
               MessageBox(NULL, "CTRL-y was pressed\nLaunch your app here", "H O T K E Y", MB_OK); 
               CTRL_key=0;
            }

            if (CTRL_key !=0 && key == 'q' )
            {
                MessageBox(NULL, "Shutting down", "H O T K E Y", MB_OK); 
               PostQuitMessage(0);
            }




            //printf("key = %c\n", key);
            printf("ha ha, I intercepted your [%c] and changed it to [%c]\n", key, key+1);

            SHIFT_key = 0;
            CTRL_key = 0;
            ALT_key = 0;

        }

        //printf("lpszKeyName = %s\n",  lpszKeyName );
    //  printf("%s",  lpszKeyName );
    }
    return CallNextHookEx(hKeyboardHook,    nCode,wParam,lParam);
}

void MessageLoop()
{
    MSG message;
    while (GetMessage(&message,NULL,0,0)) 
    {
        TranslateMessage( &message );
        DispatchMessage( &message );
    }
}

DWORD WINAPI my_HotKey(LPVOID lpParm)
{
    HINSTANCE hInstance = GetModuleHandle(NULL);
    if (!hInstance) hInstance = LoadLibrary((LPCSTR) lpParm); 
    if (!hInstance) return 1;

    hKeyboardHook = SetWindowsHookEx (  WH_KEYBOARD_LL, (HOOKPROC) KeyboardEvent,   hInstance,  NULL    );
    MessageLoop();
    UnhookWindowsHookEx(hKeyboardHook);
    return 0;
}

int main(int argc, char** argv)
{
    HANDLE hThread;
    DWORD dwThread;

    hThread = CreateThread(NULL,NULL,(LPTHREAD_START_ROUTINE)   my_HotKey, (LPVOID) argv[0], NULL, &dwThread);

    //ShowWindow(FindWindowA("ConsoleWindowClass", NULL), false);

    if (hThread) return WaitForSingleObject(hThread,INFINITE);
    else return 1;

}

Add a global Windows hotkey without a running application

1 Answers1