 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
.NET Forum / Languages / Managed C++ / June 2005Keyboard logging functionality
I need to write a program that launches Internet Explorer, then counts how many <ENTER> keys are pressed inside IE. I've seen a lot of references to the SetWindowsHookEx() API call, but all sources I found seem to be piece-meal and incomplete. I'm using VC++ .NET, and would rather avoid using the WinAPI, if possible. Is there an easier way (perhaps using .NET) to do this? >I need to write a program that launches Internet Explorer, See CreateProcess(). It will return a process identifier and a thread identifier which will come in handy shortly. > then counts how many <ENTER> keys are pressed inside IE. I've seen a lot > of references to the SetWindowsHookEx() API call, but all sources I found > seem to be piece-meal and incomplete. :-) Well, they probably demonstrate how to intercept keystrokes but not how to implement your task. > I'm using VC++ .NET, and would rather avoid using the WinAPI, > if possible. Is there an easier way (perhaps using .NET) to do this? I don't believe so. One way to attack the problem would be with a system wide keyboard hook which must necessarily be implemented in a DLL. You'd only be interested in notifications where the WPARAM parameter of the notification is VK_ENTER and where the high bit (#31) of the LPARAM parameter is 0. When that's the case you'd call GetFocus() to find the active window (that's the destination of the keystroke) and then GetWindowThreadProcessId() to find either the identifier of that the owning process or thread. You'd compare either against what you got from CreateProcess() and on a match increment your count. That method is not at all specific to IE but would work with any process you create. IE does permit itself to be extended with add-ons so there _may_ be some easier way inside one of these extensions. You might want to search for a group devoted to IE to see if there is some easier way. By the way, why do you need to count the ENTER keys pressed? Regards, Will > By the way, why do you need to count the ENTER keys pressed? Yes, I was just thinking to myself: "Whatever on earth for??" Sounds like an interesting application. >> By the way, why do you need to count the ENTER keys pressed? > > Yes, I was just thinking to myself: "Whatever on earth for??" Sounds > like an interesting application. Some of my users log onto a website that uses an ActiveX control to log onto an AS/400 (within the web browser). We get charged for every "screen" sent from the server, which happens whey they hit ENTER. To avoid having to make them keep track of how many screens they see, I can just count the ENTER keys. I see that I can use WH_KEYBOARD_LL to create a global hook WITHOUT having a separate DLL, but I can't find any examples anywhere. The only code I see is for VB or C#. Do either of you know of any?? I'd even take a "with the DLL" example if nothing better can be found... > I see that I can use WH_KEYBOARD_LL to create a global hook WITHOUT having > a separate DLL, but I can't find any examples anywhere. Hmm, where do the docs say that? In the help entry for SetWindowsHookEx() their is a table in which the WH_KEYBOARD_LL hook is listed as having only global scope. Then in the remarks for the HOOKPROC parameter in the call there is this <quote> [in] Pointer to the hook procedure. If the dwThreadId parameter is zero or specifies the identifier of a thread created by a different process, the lpfn parameter must point to a hook procedure in a dynamic-link library (DLL). Otherwise, lpfn can point to a hook procedure in the code associated with the current process. </quote> Taken together that means that a DLL is required, no? > is for VB or C#. Do either of you know of any?? I'd even take a "with the > DLL" example if nothing better can be found... There is old C code for a global hook in the file Hook.c in the Platform SDK's directory Samples\multimedia\gdi\WinCap32 Note its use of the hook is canonical in that the hook detects a condition but does NOT handle it. It posts a message back to the application which planted the hook and that application is the one that handles it. This is the right way because a) Global hooks should have small footprints as they bloat _every_ windowed application b) Their code runs in the context of the application being hooked. An errant hook can crash an otherwise fine application Regards, Will >>I see that I can use WH_KEYBOARD_LL to create a global hook WITHOUT having >>a separate DLL, but I can't find any examples anywhere. [quoted text clipped - 35 lines] > Regards, > Will In experts exchange, as well as a few other sites, people mentioned that with that hook, you didn't have to have your code in a separate DLL. So, the main code to be managed, and I guess the DLL code needs to be unmanaged?? What type of a project is the DLL? Is there no code that is designed for VC++ .NET? > In experts exchange, as well as a few other sites, people mentioned that > with that hook, you didn't have to have your code in a separate DLL. Hmm. To hook a process other than the one in which the SetWindowsHookEx() call is made. Sounds hokey to me. > So, the main code to be managed, and I guess the DLL code needs to be > unmanaged?? What type of a project is the DLL? The DLL would be native. If you are using VS.Net 2003 you first select C++ projects and then click on the Win32 icon. Then click Application Settings and choose the DLL option. A > Is there no code that is designed for VC++ .NET? As far as I know, no. Realize that I don't claim to be a .Net expert. Regards, Will >>In experts exchange, as well as a few other sites, people mentioned that >>with that hook, you didn't have to have your code in a separate DLL. [quoted text clipped - 15 lines] > Regards, > Will Ok, well with the callback code in a separate DLL, how will I get the "ENTER count" back into my managed code? > Ok, well with the callback code in a separate DLL, how will I get the > "ENTER count" back into my managed code? You adopt some interprocess communication mechanism between the DLL (which runs in the applications being hooked) and your application which planted the hook (presumably via some form of interop). The sample to which I pointed posts a WM_COMMAND message. You code do that. Of course, that begs the question as to how you retrieve the message on the managed side. It's not something that I've done so I can't offer any advice. IMO, what you are trying to do is best done natively, anyway. Regards, Will >> Yes, I was just thinking to myself: "Whatever on earth for??" Sounds >> like an interesting application. [quoted text clipped - 4 lines] > to make them keep track of how many screens they see, I can just count the > ENTER keys. You may consider another approach to handle this case (case of using ActiveX in the Internet Explorer): 1. Create alternative ActiveX, which mimics interface of the original ActiveX and forwards all requests to it. 2. Implement there your tracing logic. 3. Register ActiveX substitution for the Internet Explorer in the registry: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{original guid}] "AlternateCLSID"="{substitution guid}" "Compatibility Flags"=dword:00000000  SignatureVladimir Nesterovsky e-mail: vladimir@nesterovsky-bros.com home: http://www.nesterovsky-bros.com
Free MagazinesGet these publications absolutely FREE for up to 12 months. There are no hidden fees and no obligation. Simply choose a title, complete the application form and submit it. Read more ...
|
Reply to this Message
|
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.