Visual Basic

Re: Detecting keyboard and mouse on locked computer

5-Oct-09 6:40

RyJaBy wrote:
Is is at all possible to detect mouse movement or keyboard strokes while the computer is locked by the user?

I don't know if it would work if the computer is locked, but the only way you could do that would be to implement global keyboard and mouse hooks.

Google for "vb.net global keyboard hook" and you'll find examples.

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Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Eddy Vluggen5-Oct-09 6:58

Eddy Vluggen

5-Oct-09 6:58

Dave Kreskowiak wrote:
I don't know if it would work if the computer is locked,

That would definitely be uncool, since one could read keystrokes that are meant for Gina's eyes only Frown | :(

I are Troll Smile | :)

Re: Detecting keyboard and mouse on locked computer

Dave Kreskowiak5-Oct-09 8:47

Re: Detecting keyboard and mouse on locked computer

5-Oct-09 8:47

Yeah, I kind of knew that, though my "recall" is a bit hampered today because of a lack of sleep. Big Grin | :-D

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Luc Pattyn5-Oct-09 7:45

Re: Detecting keyboard and mouse on locked computer

5-Oct-09 7:45

Isn't a locked computer showing another desktop, kind of a parallel universe, to which your regular "global keyboard and mouse hooks" have no access? Otherwise GINA would be in trouble as Eddy pointed out.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

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Dave Kreskowiak5-Oct-09 8:46

Re: Detecting keyboard and mouse on locked computer

5-Oct-09 8:46

Yeah, I'd be willing to say it won't work at all. I gave him an avenue to try though.

Yep, the Unlock screen is shown on a completely seperate Desktop than the one the user sees.

His only other option would be to write a new GINA. Good Luck with that! Laugh | :laugh:

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

RyJaBy7-Oct-09 4:22

RyJaBy

7-Oct-09 4:22

Okay so if I cant detect the keyboard while it is locked, is there a way to determine if the computer gets locked? Is there a specific event that is triggered when the computer gets locked?

Re: Detecting keyboard and mouse on locked computer

Dave Kreskowiak7-Oct-09 10:25

Problem Reading Network Packet Data

7-Oct-09 10:25

If you're running this on Windows XP SP2 and above and you're using .NET 2.0 or better you can use the SystemEvents.SessionSwitch event. You have to wire this event up and tear it down yourself though.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

phil24155-Oct-09 4:39

5-Oct-09 4:39

I hope nobody gets upset about me starting a new thread - I've posted a couple about this project already but the problems I'm encountering are different each time.

The server application I've written in Visual Basic is receiving a packet of data from a client. I have had nothing to do with how the client communicates, and I can't change it - I'm sort of trying to 'reverse engineer' an existing application.

A packet sniffer tells me what the data of the packet from the client contains. In hex it is:

414D464D1A000000BD020012FB21CC1F0600000053746F636B73

The same packet sniffer software tells me that this converts to:

AMFM....½...û!Ì.....Stocks

The word 'Stocks' at the end is the client name, so obviously that's what I'm trying to obtain. I have no idea what the other bits mean.

But when the little application I've written receives this packet and displays the data received it only displays "AMFM". Nothing else. If I change my code to display the hex received and not the ASCII conversion it shows the whole hex code, just as the packet sniffer does.

Why does it only show me these first four characters (plus the mysterious box)? How can I get the rest?

Oddly enough, when copying the output from the packet sniffer to the clipboard as I wrote this, even though I selected the whole string when I pasted it into my browser window it only pasted "AMFM". What's going on?!

Luc Pattyn5-Oct-09 5:07

5-Oct-09 5:07

Not all data is text, some is just binary data; and some is mixed (as in an EXE file).
Text processing often stops at the first NULL character, which is a zero byte.
The non-user content of TCP/IP packets is documented in the TCP/IP documentation.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

phil24155-Oct-09 5:10

5-Oct-09 5:10

By "non-user content" are you referring to the header information and so forth? I'm already ignoring all of that, this is just the part identified as "data" by the packet sniffer.

Is there a way to have my code continue to look for text in the string after it encounters a null byte? Or just to read the last characters of the string, which seem to constitute the client name?

Dave Kreskowiak5-Oct-09 5:26

5-Oct-09 5:26

You'll have to go over the byte data yourself and look for alphanumeric ASCII values. Relying on the Encodings classes to do it for you will all result in stopping at the first 0 byte they encounter.

You're going to have a very difficult time with this. It's like you're trying to speak Japanese by duplicating the sounds of the words you hear instead of understanding the language.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

phil24155-Oct-09 5:31

5-Oct-09 5:31

And here was me thinking I'd had a difficult time up until now! I like your analogy - but if this packet contains data in a 'foreign language', what does speak this language?

So in theory if I create a loop which works through every byte in the string looking for characters with ASCII values between 32 and 126 and adds them to a string if they match those criteria that should work?

/sigh

Dave Kreskowiak5-Oct-09 6:36

5-Oct-09 6:36

phil2415 wrote:
So in theory if I create a loop which works through every byte in the string looking for characters with ASCII values between 32 and 126 and adds them to a string if they match those criteria that should work?

You'll get some form of data. Whether or not it means anything is a whole other issue.

How about this? 1, 16, 32464, 2342, 6547. What does that string of numbers mean? Without knowing precisely what the applications send back and forth and how it's formatted by the applications, you have no hope of ever understanding what the numbers mean, nor how to respond in a manner that's going to be understood.

Also, if the data object thats being transferred is bigger than one packet, how will you know??

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Luc Pattyn5-Oct-09 5:30

5-Oct-09 5:30

Hi,

if all the sniffer knows is Ethernet packets, then it would strip Ethernet heads and tails, and call the remainder "data". However other protocols are built on top of that, each adding either entire packets, or pre- and postfixing their own header and tail to the actual user data.

research TCP/IP, it is all standardized and documented and slightly complex if you're new to it.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

phil24155-Oct-09 5:34

5-Oct-09 5:34

Luc Pattyn wrote:
slightly complex

Slightly?! :p

Thanks for the help, I'll crack on and read the documentation!

Luc Pattyn5-Oct-09 5:43

5-Oct-09 5:43

Not immediately recognizing some hex output doesn't necessarily make it complex.

if you want something complex, have a look at PEF, the file format used by Windows executables.

Smile | :)

Luc Pattyn

Local announcement (Antwerp region): Lange Wapper? Neen!

Dave Kreskowiak5-Oct-09 6:39