The function below is logging the "0", "z" and the "1" ok... but its not capturing the "Z" (shift-z)... any help would be appreciated...
__declspec(dllexport)
LRESULT CALLBACK HookProc (UINT nCode, WPARAM wParam, LPARAM lParam)
{
if ((nCode == HC_ACTION) && (wParam == WM_KEYUP))
{
// This Struct gets infos on typed key
KBDLLHOOKSTRUCT hookstruct = *((KBDLLHOOKSTRUCT*)lParam);
// Bytes written counter for WriteFile()
DWORD Counter;
wchar_t Logger[1];
switch (hookstruct.vkCode)
{
case 060: Logger[0] = L'0'; break;
case 061: Logger[0] = L'1'; break;
case 90: Logger[0] = L'z'; break;
case 116: Logger[0] = L'Z'; break;
}
// Opening of a logfile. Creating it if it does not exists
HANDLE hFile = CreateFile(L"C:\\logfile.txt", GENERIC_WRITE,
FILE_SHARE_READ, NULL,OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
// put the file pointer to the end
SetFilePointer(hFile,NULL,NULL,FILE_END);
// Write the hFile typed in logfile
WriteFile(hFile,&Logger,sizeof(Logger),&Counter,NULL);
//WriteFile(hFile,&hookstruct.vkCode,sizeof(hookstruct.vkCode),&Counter,NULL);
// Close the file
CloseHandle(hFile);
}
}
The keyboard does not send characters. It sends keys. Whether you're typing z or Z, you're still pressing the same key, and that key has the same VK code both times.
You should also get notification when the Shift key is pressed or released. You can use those notifications to translate the keystrokes into characters. The caps-lock state will also be relevant for that. You may also be concerned about dead keys.
You can check whether the Shift key is pressed. GetAsyncKeyState will tell you the state of the key right now, and GetKeyState will tell you the state of the key as of the last message removed from the message queue.
There's no virtual key code for Z.
Try something like this:
case 90:
if(GetKeyState(VK_LSHIFT|VK_RSHIFT)
Logger[0] = L'Z'; break;
else
Logger[0] = L'z'; break;
Related
I am trying to write a simple global keyboard hook program to redirect some keys. For example, when the program is executed, I press 'a' on the keyboard, the program can disable it and simulate a 'b' click. I do not need a graphic ui, just a console is enough (keep it running)
My plan is to use global hook to catch the key input, and then use keybd_event to simulate the keyboard. But I have some problems.
The first problem is that the program can correctly block 'A' but if I hit 'A' on the keyboard once, the printf in the callback function is executed twice, as well as the keybd_event. So if i open a txt file, i click 'A' once, there are two 'B's input. why is that?
The second question is that why the hook using of WH_KEYBOARD_LL can work on other process without a dll? I thought that we had to use a dll to make a global hook until I wrote this example...
#include "stdafx.h"
#include <Windows.h>
#define _WIN32_WINNT 0x050
LRESULT CALLBACK LowLevelKeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
BOOL fEatKeystroke = FALSE;
if (nCode == HC_ACTION)
{
switch (wParam)
{
case WM_KEYDOWN:
case WM_SYSKEYDOWN:
case WM_KEYUP:
case WM_SYSKEYUP:
PKBDLLHOOKSTRUCT p = (PKBDLLHOOKSTRUCT)lParam;
if (fEatKeystroke = (p->vkCode == 0x41)) { //redirect a to b
printf("Hello a\n");
keybd_event('B', 0, 0, 0);
keybd_event('B', 0, KEYEVENTF_KEYUP, 0);
break;
}
break;
}
}
return(fEatKeystroke ? 1 : CallNextHookEx(NULL, nCode, wParam, lParam));
}
int main()
{
// Install the low-level keyboard & mouse hooks
HHOOK hhkLowLevelKybd = SetWindowsHookEx(WH_KEYBOARD_LL, LowLevelKeyboardProc, 0, 0);
// Keep this app running until we're told to stop
MSG msg;
while (!GetMessage(&msg, NULL, NULL, NULL)) { //this while loop keeps the hook
TranslateMessage(&msg);
DispatchMessage(&msg);
}
UnhookWindowsHookEx(hhkLowLevelKybd);
return(0);
}
Many thanks!
Your callback function execute twice because of WM_KEYDOWN and WM_KEYUP.
When you down a key of your keyboard, windows calls the callback function with WM_KEYDOWN message and when you release the key, windows calls the callback function with WM_KEYUP message. That's why your callback function execute twice.
You should change your switch statement to this:
switch (wParam)
{
case WM_KEYDOWN:
case WM_SYSKEYDOWN:
case WM_KEYUP:
case WM_SYSKEYUP:
PKBDLLHOOKSTRUCT p = (PKBDLLHOOKSTRUCT)lParam;
if (fEatKeystroke = (p->vkCode == 0x41)) //redirect a to b
{
printf("Hello a\n");
if ( (wParam == WM_KEYDOWN) || (wParam == WM_SYSKEYDOWN) ) // Keydown
{
keybd_event('B', 0, 0, 0);
}
else if ( (wParam == WM_KEYUP) || (wParam == WM_SYSKEYUP) ) // Keyup
{
keybd_event('B', 0, KEYEVENTF_KEYUP, 0);
}
break;
}
break;
}
About your second question, I think you have already got from #Ivan Danilov answer.
First one is easy. You get one for key down and another for key up. :)
As for the why it can work without a DLL - that's because it is a global hook. Unlike thread-specific ones it is executed in your own process, not in the process where keyboard event happened. It is done via message sending to the thread which has installed the hook - that's precisely why you need message loop here. Without it your hook can't be ran as there would be no one to listen for incoming messages.
The DLL is required for thread-specific hooks because they're called in the context of another process. For this to work, your DLL should be injected into that process. It is just not the case here.
I have run your code but nothing happend? What wrong with me?
Base on msdn that WH_KEYBOARD_LL message is "Global only" It mean more than that.
The system calls this function .every time a new keyboard input event is about to be posted into a thread input queue.
This message is special case. You also need an DLL to make a real global hook for other message.
I'm trying to learn WinAPI programming but now I got stuck with this problem - I want to get pressed key and show it. I have this piece of code
LRESULT CALLBACK WndProc(HWND hwnd, UINT Msg, WPARAM wParam, LPARAM lParam){
switch(Msg){
case WM_CREATE:
break;
case WM_CHAR:
char ascii_code = wParam;
unsigned int key_state = lParam;
SetWindowText(hwndStatic, TEXT("You pressed key "+ascii_code));
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
}
return DefWindowProc(hwnd, Msg, wParam, lParam);
}
but the output is weird... It shows random messages(different for each key). What am I doing wrong?
I tried to debug it (step by step) and the ascii_code contains the pressed key but the TEXT() doesn't show it.
You can't add characters together like this:
"You pressed key "+ascii_code;
This will take the address of "You pressed key ", e.g. 1000 and add the ascii code value to it, e.g. 95.
The function will try to print the string at memory address 1095. It will print all the memory until it hits a null character (zero). This could be anything.
You need to either use C functions to build your string, or, as this is tagged C++ use std::string.
std::string message = "You pressed key ";
message += ascii_code;
SetWindowText(hwndStatic, TEXT(message.c_str()))
"You pressed key "+ascii_code
You cannot concatenate strings like that. The real type of "foo bar" is const char[8] - a raw C-like array of characters. When you apply + on it, it decays to a pointer to its first element and the operation is carried on the pointer. This means you end up printing some random data based on where this pointer ends up pointing in the end.
If you want to concatenate a character to a string, you have to use more intelligent string representation, such as std::string:
(std::string("you pressed key ") + ascii_code).c_str();
I am trying to capture the values of WM_CHAR keys, and then putting all the captured the values into a single string. I have tried to concatenate the pressed key value 2, 3, 4 and 5 with _tcscat, the resulting TCHAR string looks like this "22232323423423452345" I would like to know how to make TCHAR string looks like 2345. The following is the code that I have.
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static PMSG pmsg ;
int i, iType ;
int StrLen;
TCHAR StrBuf[9];
static TCHAR tBuf[32];
TCHAR MyTchar[8] = TEXT ("A");
WORD wCharCode;
switch (message)
{
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps) ;
GetClientRect(hwnd, &rect);
SelectObject (hdc, GetStockObject (SYSTEM_FONT)) ;
SetBkMode (hdc, TRANSPARENT) ;
for (i = min (cLines, cLinesMax), cScreenLine=1; i>0 ; i--, cScreenLine++)
{
iType = pmsg[i-1].message == WM_CHAR ;
if (!iType)
{
StrLen= wsprintf(StrBuf, TEXT("%s"), TEXT(" "));
}
else
{
wCharCode = (WORD)(pmsg[i-1].wParam & 0xffff);
memcpy(&MyTchar, &wCharCode, 2);
StrLen = wsprintf(StrBuf[2], TEXT("%s"), &MyTchar);
_tcscat(tBuf, MyTchar);
}
EndPaint (hwnd, &ps) ;
return 0 ;
case WM_DESTROY:
PostQuitMessage (0) ;
return 0 ;
}
}
I don't understand the message processing you have during the WM_PAINT message. You probably want to handle WM_CHAR as a separate message altogether where you can keep track of a string.
Outside of your WndProc, you will need #include <string>; and std::wstring keyPresses;
WM_CHAR can then be handled like any other event inside the WndProc.
case WM_CHAR:
switch (wParam)
{
// First, handle non-displayable characters by beeping.
case 0x08: // backspace.
case 0x09: // tab.
case 0x0A: // linefeed.
case 0x0D: // carriage return.
case 0x1B: // escape.
case 0x20: // space.
MessageBeep((UINT) -1);
break;
// Next, handle displayable characters by appending them to our string.
default:
keyPresses += (wchar_t) wParam;
}
break;
Then, you can do whatever manipulations you would like on this string, including displaying it during the WM_PAINT message.
Since you are using C++, use std::string or std::wstring. It will be much simpler and safer (no buffer overflows)
Before you use string buffer, you should clear them first.
You can use
1. ZeroMemery
2. memset
And or
TCHAR StrBuf[9];
====>
TCHAR StrBuf[9] = {0};
finally, why u use tBuf as a static var?
I have buy this keyboard http://www.mobilitylab.eu/mini-design-touch-silver.html of 107 touch,
and I want a keypad to put it on my left hand.
but when we activate the numlock of the keypad, it activates the numlock on the keyboard.
So we have 456- instead of uiop.
I have found this program but it don't work on a 64 bits OS. http://www.bellamyjc.org/fr/systeme.html#knumlock.
So i want to do my own program with C++, but it don't work fine, the hook is allright (WH_GETMESSAGE) but i don't understand how we can change the keycode and how we can find if it's a key of the keypad or the keybord ?
Here this is my code where i try to change the message :
//-----------------Keyboard Hook Callback---------------//
Hookmsg_API LRESULT CALLBACK Hookmsg(int ncode,WPARAM wparam,LPARAM lparam){
//if(ncode>=0) //
if(ncode<0)
return CallNextHookEx(hook,ncode,wparam,lparam);
MSG *msg;
msg=(MSG *)lparam;
WORD newVK,oldVK;
WORD newSC,oldSC;
if(ncode==HC_ACTION)
{
if((msg->message == WM_KEYUP))//Check whether key was pressed(not released).)
{
oldVK=msg->wParam;
oldSC=SCANCODE(msg->lParam);
bool extendkey=false;
if(((HIWORD(msg->wParam) & 0x0100) == 0x0100))
{
extendkey=true;
}
if(!extendkey)
{
bool modif=true;
switch(oldVK)//wparam
{
case VK_INSERT: newVK=VK_NUMPAD0; break;
case VK_END: newVK=VK_NUMPAD1; break;
case VK_DOWN: newVK=VK_NUMPAD2; break;
case VK_NEXT: newVK=VK_NUMPAD3; break;
case VK_LEFT: newVK=VK_NUMPAD4; break;
case VK_CLEAR: newVK=VK_NUMPAD5; break;
case VK_RIGHT: newVK=VK_NUMPAD6; break;
case VK_HOME: newVK=VK_NUMPAD7; break;
case VK_UP: newVK=VK_NUMPAD8; break;
case VK_PRIOR: newVK=VK_NUMPAD9; break;
case VK_DELETE: newVK=VK_DECIMAL; break;
default: modif=false;
}
if(modif==true)
{
msg->wParam = VK_NUMPAD0;
UINT newSC=MapVirtualKey(VK_NUMPAD0,MAPVK_VK_TO_VSC);
msg->lParam &= 0xFF00;
msg->lParam += (newSC << 16 );
//MessageBox( NULL, TEXT("OK"), TEXT("Error!"), MB_OK);
}
}
}
}
return ( CallNextHookEx(hook,ncode,wparam,lparam) );//pass control to next hook in the hook chain.
}
cant understand u...
u have 2 keyboards? if yes, try to use Raw Input (raw data from USB HID device)
http://msdn.microsoft.com/en-us/library/windows/desktop/ms645543(v=vs.85).aspx
Lparam and wparam are not visible for other applications.
Keyboard input is much more than just windows messages. Modifying the messages will work in some cases, but is a vastly incomplete solution. You also need to consider driver state, GetKeyboardState, and others.
If you want to remap keys on your keyboard, you can create a new keyboard layout and assign it to a locale.
If keyboard layouts don't satisfy your needs, you will need to write a keyboard device driver.
If you only need this functionality in a specific application (not system globally), then you might be able to get lucky and only modify windows messages.
im having a bit of trouble writing a keyboard hook in C++.
I can read keystrokes but im trying to using ToUnicodeEx() to convert keystrokes when shift key is pressed.
In the code i have so far i have
i = ToUnicodeEx(keyboard.vkCode, keyboard.scanCode, (PBYTE)&keyState, (LPWSTR)&keybuff, sizeof(keybuff) / 16, 0,keyboardlayout);
MessageBox(MainnhWnd,keybuff, L"message", MB_OK | MB_ICONEXCLAMATION);
with this 'MessageBox' line when I press Shift+2 i get two message boxes pops up, the first is blank for the shift key, the second shows a '#' character. This is expected.
But if i remove this messagebox, the ToUnicodeEx() function converts the keystroke as if the shift key had not been used. I can see this by either setting a breakpoint, with a hit counter, or outputting the character to an edit box in my program windows.
Also when i include the MsgBox line and use the CapLock, my letters change accordingly but after i remove the msgbox line it only uses the state of the cap lock at the time my program starts (cap locks is on when programm starts, all letters are capital, vice verse, caps off when programm starts all letters are small,, even if i change the cap lock state)
Anyone know why my hook just remembers the keyboard state at start, unless i include the msgbox?
My hook is set like:
theHook = SetWindowsHookEx ( WH_KEYBOARD_LL, (HOOKPROC) KeyEvent, exe, 0);
and my hook callback function is:
DLLEXPORT LRESULT CALLBACK KeyEvent(int nCode, WPARAM wParam, LPARAM lParam) {
if (nCode>=0) {
int i = 0;
KBDLLHOOKSTRUCT keyboard;
WCHAR keybuff[256]= {0};
if ((wParam == WM_KEYDOWN)|| (wParam == WM_SYSKEYDOWN)||(wParam == WM_SYSKEYUP)) {
keyboard = *((KBDLLHOOKSTRUCT*)lParam);
if (keyboard.vkCode == VK_RETURN) {
i += wsprintf (((LPWSTR)keybuff + i),L"[Return]\r\n");
}
else {
HKL keyboardlayout = GetKeyboardLayout(0);
GetKeyboardState((PBYTE)&keyState);
i = ToUnicodeEx(keyboard.vkCode, keyboard.scanCode, (PBYTE)&keyState, (LPWSTR)&keybuff, sizeof(keybuff) / 16, 0,keyboardlayout);
MessageBox(MainnhWnd,keybuff, L"message", MB_OK | MB_ICONEXCLAMATION);
}
if (keybuff>0) {
addToEditBox(keybuff);
}
}
}
return CallNextHookEx(theHook, nCode, wParam, lParam);
}
According to documentation of ToUnicodeEx function, you should provide a pointer to a 256-byte array that contains the current keyboard state (const BYTE *lpKeyState). Each element (byte) in the array contains the state of one key. If the high-order bit of a byte is set, the key is down.
Before you call ToUnicodeEx, you should set this array like this (pseudocode):
enum Keys
{
ShiftKey = 16, // shift
ControlKey = 17, // ctrl
Menu = 18, // alt
Capital = 20, // caps lock
};
BYTE keyState[256]= {0};
if (Control key down)
keyState[Keys::ControlKey] = 0x80;
if (Shift key down)
keyState[Keys::ShiftKey] = 0x80;
if (Alt key down)
keyState[Keys::Menu] = 0x80;
if (Caps lock ON)
keyState[Keys::Capital] = 0x01;
And when keyState array is set, then you can call:
ToUnicodeEx(keyboard.vkCode, keyboard.scanCode, (PBYTE)&keyState, (LPWSTR)&keybuff, sizeof(keybuff) / 16, 0,keyboardlayout);
I have been working with ToUnicodeEx function just like this and it worked fine.
Hope this will help you ;)