I've been trying to set up a CBT hook for my C++ Console application with the following code:
...includes...
typedef struct _HOOKDATA
{
int type;
HOOKPROC hookproc;
HHOOK hhook;
}_HOOKDATA;
_HOOKDATA hookdata;
//CBT
LRESULT CALLBACK CBTProc(int code, WPARAM wParam, LPARAM lParam)
{
//do not proccess message
if(code < 0)
{
cout<<"code less than 0"<<endl;
return CallNextHookEx(hookdata.hhook,code,wParam,lParam);
}
switch(code)
{
case HCBT_ACTIVATE:
break;
case HCBT_CREATEWND:
cout<<"CREATEWND"<<endl;
break;
case HCBT_MINMAX:
cout<<"MINMAX"<<endl;
break;
default: //unknown
cout<<"DEFAULT"<<endl;
break;
}
return CallNextHookEx(hookdata.hhook, code, wParam, lParam);
}
int main()
{
hookdata.type = WH_CBT;
hookdata.hookproc = CBTProc;
hookdata.hhook = ::SetWindowsHookEx(hookdata.type, CBTProc,
GetModuleHandle( 0 ), GetCurrentThreadId());
if(hookdata.hhook == NULL)
{
cout<<"FAIL"<<endl;
system("pause");
}
system("pause");
return 0;
}
The program seems to be working because there is not compile errors nor run time errors. Also I do not get a 'FAIL' message stated in the main() function meaning SetWindowHookEx is working OK. However, I don't get any of the messages stated in the CBTProc function; not even the 'DEFAULT' message. Can anyone pin-point what is the logic error in the code?
Thanks.
The problem is that SetWindowHookEx is based upon the Win32 message handling model. Console windows are children of the Kernel itself and do not create their own message pumps or windows.
AFAIK doing what you want directly is not possible.
Related
I would like to hook Windows Explorer paste event to copy files from a remote connection.
Description: The goal is remote copy/paste files. Like Team Viewer or Remote Desktop. Ctrl+C file on one computer, and Ctrl+V on another...
Well let's break this problem into 3 parts:
1. Detect for clipboard changes:
This is pretty easy, by registering a hook using SetClipboardViewer, Windows will nicely send us an WM_DRAWCLIPBOARD message:
HWND nextClipboardViewer = nullptr;
void HandleClipboardChanges()
{
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_CREATE:
nextClipboardViewer = SetClipboardViewer(hwnd);
break;
case WM_CHANGECBCHAIN:
if (reinterpret_cast<HWND>(wParam) == nextClipboardViewer)
{
nextClipboardViewer = reinterpret_cast<HWND>(lParam);
}
else if (nextClipboardViewer != nullptr)
{
SendMessage(nextClipboardViewer, msg, wParam, lParam);
}
break;
case WM_DRAWCLIPBOARD:
HandleClipboardChanges();
SendMessage(nextClipboardViewer, msg, wParam, lParam);
break;
}
}
2. Get the active Windows Explorer directory
In the HandleClipboardChanges function above, we should iterate through all the opened Windows Explorer, check if any of them is focused, and get their current directory, thanks to zett42's answer, we could do this fairly easily:
HWND hWndExplorer = nullptr;
HWND hWndFocused = GetActiveWindow();
std::wstring explorerDir;
for (const auto& info : GetCurrentExplorerFolders())
{
if (hWndFocused == info.hwnd)
{
CComHeapPtr<wchar_t> pPath;
if (SUCCEEDED(::SHGetNameFromIDList(info.pidl.get(), SIGDN_FILESYSPATH, &pPath)))
{
hWndExplorer = info.hwnd;
explorerDir = pPath;
}
break;
}
}
3. Handle the copy operation and show a progress dialog
For the progress dialog, we will use IProgressDialog, although IOperationsProgressDialog has more features, but it is also more difficult to use, you can consider switching to it.
The hWndParent passed into IProgressDialog::StartProgressDialog could be nullptr, but we will use the explorer's hWnd for consistency.
The below code doesn't check for errors for readability.
// don't forget the include and CoInitialize
#include <atlbase.h>
#include <shlobj_core.h>
CoInitializeEx(nullptr, COINIT_MULTITHREADED);
CComPtr<IProgressDialog> pDialog;
pDialog.CoCreateInstance(CLSID_ProgressDialog);
pDialog->StartProgressDialog(hWndExplorer, nullptr, PROGDLG_AUTOTIME, nullptr);
pDialog->SetTitle(L"Copying from network");
pDialog->SetLine(1, L"Copying 69 files", false, nullptr);
// Do your copy operation here
for (DWORD i = 0; i < 1'000'000; i++)
{
pDialog->SetProgress(i, 1'000'000);
pDialog->SetLine(2, L"Copying file_a.txt", false, nullptr);
// Check if the user had cancelled the operation
// See also: pDialog->SetCancelMsg()
// BOOL isUserCancelled = pDialog->HasUserCancelled();
}
pDialog->StopProgressDialog();
Related:
Monitoring clipboard
How to get the path of an active file explorer window in c++ winapi
I suddenly started receiving this failure and I cannot figure out why. In the error message, the program is listed as mfc140d.dll and the specific file as "...\mfc\winctrl1.cpp". It seems only windows references this section of code. Specifically, it is failing at "void CComboBox::MeasureItem(…)" function.
Before, I was running my application just fine. I can't imagine what would have happened to cause this error to suddenly show up. Truth be told, I'm pretty unsure of what this code does as is. I know very little about mfc apps.
void CComboBox::DrawItem(LPDRAWITEMSTRUCT)
{ ASSERT(FALSE); }
void CComboBox::MeasureItem(LPMEASUREITEMSTRUCT)
{ ASSERT(FALSE); }
int CComboBox::CompareItem(LPCOMPAREITEMSTRUCT)
{ ASSERT(FALSE); return 0; }
void CComboBox::DeleteItem(LPDELETEITEMSTRUCT)
{ /* default to nothing */ }
BOOL CComboBox::OnChildNotify(UINT message, WPARAM wParam, LPARAM lParam,
LRESULT* pResult)
{
switch (message)
{
case WM_DRAWITEM:
ASSERT(pResult == NULL); // no return value expected
DrawItem((LPDRAWITEMSTRUCT)lParam);
break;
…
I am setting a global hook for keyboard. When I give keyboard inputs to other applications, the application does not receive the input and it hangs. When the console is stopped, the application recovers and the keyboard inputs are posted together.
DLL source:
#include <iostream>
#include <Windows.h>
#include <string>
using namespace std;
#define DLLEXPORT __declspec(dllexport)
DLLEXPORT bool installhook();
DLLEXPORT void unhook();
DLLEXPORT string TestLoaded();
DLLEXPORT LRESULT CALLBACK KeyboardProc ( int code, WPARAM wParam, LPARAM lParam );
static HHOOK kb_hook;
string test = "not loaded";
HINSTANCE hDLL;
DLLEXPORT LRESULT CALLBACK KeyboardProc ( int code, WPARAM wParam, LPARAM lParam )
{
if(code == HC_ACTION) // if there is an incoming action and a key was pressed
{
switch(wParam)
{
case VK_SPACE:
printf("Space was pressed\n"); //tried without this also
MessageBoxA(NULL, "Hi", "Space", MB_OK);
break;
}
}
return CallNextHookEx(NULL, code, wParam, lParam);
}
BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
{
test = "loaded";
switch(ul_reason_for_call)
{
case DLL_PROCESS_ATTACH:
hDLL = hModule;
break;
}
printf("test str = %s \n", test.c_str());
return TRUE;
}
bool installhook()
{
kb_hook = SetWindowsHookEx(WH_KEYBOARD, KeyboardProc, hDLL, NULL);
if(!kb_hook)
{
return false;
}
return true;
}
void unhook()
{
if(kb_hook)
{
UnhookWindowsHookEx(kb_hook);
}
}
string TestLoaded()
{
return test;
}
Console applicatioon source:
#include <iostream>
#include <Windows.h>
#include <string>
#define DLLIMPORT __declspec(dllimport)
using namespace std;
DLLIMPORT void unhook();
DLLIMPORT bool installhook();
DLLIMPORT string TestLoaded();
int main()
{
cout << TestLoaded() <<endl;
installhook();
for(int i = 1; i<=10 ; i++)
{
//Do some keyboard activities in this 10 secs
Sleep(1000);
cout << i<<endl;
}
unhook();
cin.get();
return 1;
}
My suspicion was that since the dll will be loaded into each process in the process's own address space and console would not be present in other applications, it gets void and crashed. So I removed the console outputs and replaced with messagebox. Then also no difference.
What could be the problem?
Update:
I tried to do a local hook to a specific thread before trying it global. But I get Parameter is incorrect error 87 at setwindowshookex. Below are the updated code:
dll:
bool installhook(DWORD ThreadId) //exporting this function
{
kb_hook = SetWindowsHookEx(WH_KEYBOARD, KeyboardProc, NULL, ThreadId); //tried with the dll module's handle also instead of NULL
if(!kb_hook)
{
printf("SetWindowsHookEx failed : %d\n", GetLastError());
return false;
}
return true;
}
Console application source:
DWORD myThread()
{
cout<< "Thread started\n";
char str[250];
cin>>str;
return 0;
}
int main()
{
cout << TestLoaded() <<endl;
DWORD myThreadID;
HANDLE myHandle = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)myThread, NULL, 0, &myThreadID);
installhook(myThreadID);
for(int i = 0; i<100 ; i++)
{
Sleep(100);
if(i%10 == 0)
{
cout << i<<endl;
}
}
unhook();
}
Try to use WH_KEYBOARD_LL. You can set global hook even without dll declaring hook function in you process. Plus, you should detect space action using PKBDLLHOOKSTRUCT struct
LRESULT CALLBACK KeyboardProc ( int code, WPARAM wParam, LPARAM lParam )
{
if ( code == HC_ACTION )
{
switch ( wParam )
{
case WM_KEYDOWN:
{
// Get hook struct
PKBDLLHOOKSTRUCT p = ( PKBDLLHOOKSTRUCT ) lParam;
if ( p->vkCode == VK_SPACE)
{
MessageBoxA( NULL, "Hi", "Space", MB_OK );
}
}
break;
}
}
return CallNextHookEx( NULL, code, wParam, lParam );
}
....
// Somewhere in code
kb_hook = SetWindowsHookEx( WH_KEYBOARD_LL, KeyboardProc, NULL, NULL );
Thanks for all the inputs in answers and comments.
I have found out the actual problem. The mistake I made was trying to use console window without any message queue.
If I understand correctly, console windows are hosted by conhost.exe and they don't have any message pumps. And the hook works correctly only if the application which installs it has a message queue (should explore more on why it's this way). See below for ways you can make it work
If you are not posting any message to the console application:
Replace the for loop in the console application's main with this:
MSG msg;
while(GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
In case you are posting any message to the console application:
Create a window using CreateWindowEx, there is an option for a message only window also. You would have to create a class and assign a CALLBACK process. Read here for more details. Create that and pass the handle along to the hook dll and postmessage to the handle. Use the loop for Getting msg and dispatching it (mentioned above). Then all the messages you post the dummy window from your hook dll can be processed using the CALLBACK window process.
References:
Why must SetWindowsHookEx be used with a windows message queue
CreateWindowEx MSDN
I had the same issue, working with QT, the GUI would be blocked (as planned) but whenever it came back online, it would process my keyboard and mouse clicks.
I am not sure if this is the most efficient way of handling it, but to solve this, I handled all the keyboard and mouse events separately. If, some task was in progress, I would just ignore the key event.
Otherwise I guess it just queues up and waits for its' turn!
I want my application to hook remote connect and disconnect events for all sessions on the specified computer.
According to the documentation, I should call WTSRegisterSessionNotification function first:
WTSRegisterSessionNotification(hWnd, NOTIFY_FOR_ALL_SESSIONS);
Then in the messages processor callback I should do the required stuff on WM_WTSSESSION_CHANGE message type:
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_WTSSESSION_CHANGE:
{
// do stuff
break;
}
}
}
It works very strange however. Every time I connect or disconnect to/from the computer where my application running, WTS_REMOTE_CONNECT or WTS_REMOTE_DISCONNECT called twice -- in one of these calls I can get user name and in another I can't (it's just an empty string).
case WM_WTSSESSION_CHANGE:
{
const int reason = (int)wParam;
const DWORD sessionId = (DWORD)lParam;
switch (reason)
{
case WTS_REMOTE_CONNECT:
{
DWORD bytesReturned = 0;
LPSTR pData = NULL;
if (WTSQuerySessionInformationA(WTS_CURRENT_SERVER_HANDLE, sessionId, WTSUserName, &pData, &bytesReturned) == 0)
{
// Handle error
break;
}
const std::string username = pData;
WTSFreeMemory(pData);
// do other stuff
I found this question but it has very strange accepted answer:
Hmm, the answer appears to be that it's fairly normal for these fields
to be empty on a terminal services/RDP session
I don't understand why it actually works this way.
I am developing a Notepad++ plugin.
I have a simple dialog box, which is created using CreateDialogParam(). It is initially hidden.
After a menu click, I call ShowWindow() with SW_SHOW on its handle, which results in this exception:
c000041d
Upon debugging , I found that these two messages are sent to my dialog just before crash
WM_SHOWWINDOW
WM_WINDOWPOSCHANGING
Both of them, I am not handling. Here is my dlgproc code. Any idea why it would happen ?
BOOL CALLBACK StaticDialog::dlgProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_INITDIALOG :
{
// Get the additional init data
StaticDialog *pStaticDlg = (StaticDialog *)(lParam);
// Store the handle in the object
pStaticDlg->_hSelf = hwnd;
::SetWindowLongPtr(hwnd, GWL_USERDATA, (long)lParam);
// Store the co-ordinates in the object
::GetWindowRect(hwnd, &(pStaticDlg->_rc));
// Forward the message for further processing
pStaticDlg->run_dlgProc(message, wParam, lParam);
// TRUE if it processed the message
return TRUE;
}
default :
{
// Retrieve the user data
StaticDialog *pStaticDlg = (StaticDialog *)(::GetWindowLongPtr(hwnd, GWL_USERDATA));
if (!pStaticDlg)
return FALSE;
// Send the message for further processing
return pStaticDlg->run_dlgProc(message, wParam, lParam);
// return FALSE if it processed the message
}
}
}
BOOL CALLBACK MarkDownViewDialog::run_dlgProc( UINT Message, WPARAM wParam, LPARAM lParam)
{
switch (Message)
{
case WM_INITDIALOG:
{
EmbedBrowserObject(this->_hSelf);
DisplayHTMLPage(this->_hSelf,L"http://www.microsoft.com");
DisplayHTMLStr(this->_hSelf, L"<H2><CENTER>HTML string test</CENTER></H2><P><FONT COLOR=RED>This is a <U>HTML string</U> in memory.</FONT>");
break;
}
default:
break;
}
return FALSE;
}
The dialog box is created through plugin mechanism of Notpead++. I am putting the source code from its file StaticDialog.cpp. The control goes through else block in code below.
void StaticDialog::create(int dialogID, bool isRTL, bool isModeles)
{
if (isRTL)
{
DLGTEMPLATE *pMyDlgTemplate = NULL;
HGLOBAL hMyDlgTemplate = makeRTLResource(dialogID, &pMyDlgTemplate);
_hSelf = ::CreateDialogIndirectParam(_hInst, pMyDlgTemplate, _hParent, (DLGPROC)dlgProc, (LPARAM)this);
::GlobalFree(hMyDlgTemplate);
}
else
_hSelf = ::CreateDialogParam(_hInst, MAKEINTRESOURCE(dialogID), _hParent, (DLGPROC)dlgProc, (LPARAM)this);
//int i=GetLastError();
if (!_hSelf)
{
//systemMessage(_T("StaticDialog"));
return;
}
if (isModeles) {
_isModeles = isModeles;
::SendMessage(_hParent, NPPM_MODELESSDIALOG, MODELESSDIALOGADD, (WPARAM)_hSelf);
}
}
My entire solution source code is hosted here:
https://github.com/madhur/Npp-Markdown-Viewer
Issue Resolution
Here is what I have done to troubleshoot the problem:
Created a Win32 project in which I create a dialog box and put exactly same source code to embed browser control in WM_INITDIALOG and it works. This Win32 project links with the same static library, which the original source code is linking with. This is the source of the sample project mail file:
https://github.com/madhur/Npp-Markdown-Viewer/blob/master/dll/example/example.c
The static library I referenced above, is nothing but it contains functions to embed browser control in HWND and to render either an URL or string. I have taken the source from here: http://www.codeguru.com/Cpp/I-N/ieprogram/article.php/c4379
This is the source of static library main file:
https://github.com/madhur/Npp-Markdown-Viewer/blob/master/dll/dll.c
If I comment this single line, the plugin works, basically it loads the dialog box without the Browser control in it:
EmbedBrowserObject(this->_hSelf);
The actual exception in Visual Studio is raised on this line:
return pStaticDlg->run_dlgProc(message, wParam, lParam);