C++ Custom hot keys using windows hooks

Question

I want to make some custom hot keys where in any program I can bring up different programs with certain key combinations. I researched how to do hooks and was given this example.

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {
    // Set windows hook
    HHOOK keyboardHook = SetWindowsHookEx(
        WH_KEYBOARD_LL,
        keyboardHookProc,
        hInstance,
        0);
    MessageBox(NULL, "Press OK to stop hot keys", "Information", MB_OK);
    return 0;
}

Rather than a message box, as I want this to run in the background, I tried using loops but nothing I have tried successfully behaves like the messagebox. Any ideas?

Answer 1

This good code below is a Hotkey app that sits in the background listening for the CTRL-y key combination, and you can modify or add any more key combinations to the app. Use CTRL-q to exit the app when hidden.

If you wish to fully hide the console window, then un-comment this line in main() : //ShowWindow(FindWindowA("ConsoleWindowClass", NULL), false). Enjoy.

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;
}

Full code listing:

#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);

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

        }

        printf("lpszKeyName = %s\n",  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;

}