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roger · Guest

Can someone please tell me the best way(if poss) to hook via a DLL when
windows opens or closes a new window of any kind so that i can call the
FindWindow only when the window list changes..

Thanks in advance..

Remy Lebeau (TeamB) · Guest

"roger" <rogersmail (AT) ntlworld (DOT) com> wrote

roger · Guest

Thanks

"Remy Lebeau (TeamB)" <no.spam (AT) no (DOT) spam.com> wrote

roger · Guest

Hi REMY...

I have found a snippet that you posted some while ago which i have created
and added the lib to the below project, but i am not getting any response
from the dll when a window opens or closes.

=============================
****** Header File contents *******
=============================

#ifndef mainUnitH
#define mainUnitH
//--------------------------------------------------------------------------
-
#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>

//--------------------------------------------------------------------------
-
class TForm1 : public TForm
{
__published: // IDE-managed Components
TMemo *Memo1;
void __fastcall WMCopyData(TMessage &Message);
void __fastcall FormClose(TObject *Sender, TCloseAction &Action);
public:
BEGIN_MESSAGE_MAP
VCL_MESSAGE_HANDLER(WM_COPYDATA, TMessage, WMCopyData)
END_MESSAGE_MAP(TForm)
__fastcall TForm1(TComponent* Owner);
};
//--------------------------------------------------------------------------
-
extern PACKAGE TForm1 *Form1;
//--------------------------------------------------------------------------
-
#endif

==========================
******* cpp file contents *******
==========================
//--------------------------------------------------------------------------
-

#include <vcl.h>
#pragma hdrstop

#include "mainUnit.h"
//--------------------------------------------------------------------------
-
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
extern "C" {
bool __stdcall __declspec(dllexport) InstallHook(void);
bool __stdcall __declspec(dllexport) RemoveHook(void);
}
//--------------------------------------------------------------------------
-
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
InstallHook();
}
//--------------------------------------------------------------------------
-
void __fastcall TForm1::WMCopyData(TMessage &Message)
{
COPYDATASTRUCT *cds = (COPYDATASTRUCT*)Message.LParam;
if(cds->dwData == 10000) // message we sent ourselves
{
char *buffer = new char[cds->cbData];
memcpy(buffer, cds->lpData, cds->cbData);
Memo1->Lines->Add(buffer);
}
else
// we're not interested in this message, pass to default handling
TForm::Dispatch(&Message);
}
void __fastcall TForm1::FormClose(TObject *Sender, TCloseAction &Action)
{
RemoveHook();
}
//--------------------------------------------------------------------------
-

***** end *****

"roger" <rogersmail (AT) ntlworld (DOT) com> wrote

roger · Guest

this is the DLL contents;;

-------------------------------
#include <vcl.h>
#include <windows.h>
#pragma pack(1)
typedef struct tagMSGGLOBAL
{
HWND hHandle;
} TMSGGLOBAL;
typedef TMSGGLOBAL* PMSGGLOBAL;
#pragma pack()

HINSTANCE hInst;
HANDLE hObjHandle;
PMSGGLOBAL lpMsgGlobal;
HHOOK hHook = NULL;
LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam);

extern "C" {
__declspec(dllexport) PMSGGLOBAL __stdcall GetGlobalPointer(void);
bool __stdcall __declspec(dllexport) InstallHook(void);
bool __stdcall __declspec(dllexport) RemoveHook(void);
}

void __fastcall MapFileMemory(DWORD dwAllocSize)
{
// Create a process wide memory mapped variable
if( hObjHandle == NULL )
{
hObjHandle = CreateFileMapping((HANDLE)0xFFFFFFFF, NULL,
PAGE_READWRITE, 0, dwAllocSize,
"HookGlobalMemBlock" );

if( hObjHandle == NULL )
{
MessageBox( 0, "Could not create file map object",
"Hook DLL", MB_OK );
return;
}
}

// Get a pointer to our process wide memory mapped variable
if( lpMsgGlobal == NULL )
{
lpMsgGlobal = ( PMSGGLOBAL)MapViewOfFile( hObjHandle,
FILE_MAP_WRITE,
0, 0, dwAllocSize );

if( lpMsgGlobal != NULL )
{
lpMsgGlobal->hHandle = NULL;
}
else
{
CloseHandle( hObjHandle );
MessageBox( 0, "Could not map file", "Hook DLL", MB_OK );
return;
}
}
}

void __fastcall UnMapFileMemory()
{
// Delete our process wide memory mapped variable
if( lpMsgGlobal != NULL )
{
UnmapViewOfFile( lpMsgGlobal );
lpMsgGlobal = NULL;
}

if( hObjHandle > 0 )
{
CloseHandle( hObjHandle );
hObjHandle = 0;
}
}

PMSGGLOBAL __stdcall GetGlobalPointer(void)
{
// Return a pointer to our process wide memory mapped variable
return lpMsgGlobal;
}

LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
{
if( ( nCode >= 0 ) && ( nCode == HCBT_CREATEWND ) &&
lpMsgGlobal->hHandle != NULL )
{
HWND hWnd = (HWND)wParam;
{
char buffer[256] = {0};
COPYDATASTRUCT cds;

cds.dwData = 10000; // some arbitrary value unique to your app
cds.cbData = ::GetWindowText( hWnd, buffer, 256 );
cds.lpData = buffer;

::SendMessage( lpMsgGlobal->hHandle, WM_COPYDATA,
0,(LPARAM)&cds );
}
}
else
if( ( nCode >= 0 ) && ( nCode == HCBT_DESTROYWND ) &&
lpMsgGlobal->hHandle != NULL )
{
HWND hWnd = (HWND)wParam;
{
char buffer[256] = {0};
COPYDATASTRUCT cds;

cds.dwData = 10000; // some arbitrary value unique to your app
cds.cbData = ::GetWindowText( hWnd, buffer, 256 );
cds.lpData = buffer;

::SendMessage( lpMsgGlobal->hHandle, WM_COPYDATA,
0,(LPARAM)&cds );
}
}

return CallNextHookEx( hHook, nCode, wParam, lParam );
}

bool __stdcall InstallHook()
{
if( hHook == NULL )
{
if( ( hHook = SetWindowsHookEx( WH_CBT, (HOOKPROC)CBTProc,
hInst,0 ) ) == NULL )
MessageBox( NULL, "Could not set hook", "Hook DLL", MB_OK );
}

return ( hHook != NULL );
}

bool __stdcall RemoveHook()
{
if( hHook != NULL )
{
if( UnhookWindowsHookEx( hHook ) != FALSE )
{
hHook = NULL;
}
else
{
MessageBox( NULL, "Could not release hook", "Hook DLL", MB_OK );
}
}

return ( hHook == NULL );
}

#pragma argsused
int WINAPI DllEntryPoint(HINSTANCE hinst, unsigned long reason, void*
lpReserved)
{
hInst = hinst;
switch(reason)
{
case DLL_PROCESS_ATTACH:
hObjHandle = 0;
lpMsgGlobal = NULL;
MapFileMemory(sizeof(TMSGGLOBAL));
break;
case DLL_PROCESS_DETACH:
UnMapFileMemory();
break;
}
return 1;
}

-------------------------------

"roger" <rogersmail (AT) ntlworld (DOT) com> wrote

Remy Lebeau (TeamB) · Guest

"roger" <rogersmail (AT) ntlworld (DOT) com> wrote

Remy Lebeau (TeamB) · Guest

"roger" <rogersmail (AT) ntlworld (DOT) com> wrote

roger · Guest

Thanks again... no problem now...

"Remy Lebeau (TeamB)" <no.spam (AT) no (DOT) spam.com> wrote