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How do I clear the control alt delete key downs when using input

I am trying to monitor keystroks...  When I use the Input after I log in to my system it says the Control LAlt and the Delete key are down and my code does not like that because the keyboard value is not corect...the Keypressed array always has 3 keys down....


Is there a way to clear them or send key ups some how to get rid of them.



Thanks for any help you can provide...


I am using Labview 8.0




Eric Horwitz


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Message 1 of 9

Hi Eric,


Where are you getting the Input Acquire vi from?  


I am guessing that the Control, Alt, and delete keys are being pressed when you press them to start the log on process.  Is that correct?


One thing you could try is having your vi remove the 3 elements of the array when it starts.


Best Regards,

Bryan H.
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Message 2 of 9

Yes Acquire is from Input palet....


And I aggree it is from the login sequance but the Key does not go up....


Only does after hitting it again...



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Message 3 of 9

Hi Eric,


Did you try resetting them manually at the beginning of your code?  Can you attach a sample VI to show what you are doing?


Best Regards,

Bryan H.
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Message 4 of 9

How would you do that...


Here are the VI's I am using...


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Message 5 of 9

Hi Eric,


I am seeing the same thing you are.  I was able to duplicate your results with a very simple VI.  When I have my VI running and I push Ctrl-Alt-Del then push cancel, all three buttons remain in the array until I push them individually again.  I also have problems when I push the windows key and L (to lock the computer)  When I do this I have to push ctrl-alt-del to log back in.  In this case the ctrl-alt-del keys are not still in the array, but the Windows Key is.


I am looking into why this is, and on some possible work arounds.


Best Regards,
Bryan H.
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Message 6 of 9

Hi Eric,


This was reported to R&D (#163449) for further investigation.


Message Edited by Hesloppy on 04-28-2009 01:18 PM
Bryan H.
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Message 7 of 9

I am having the same issue and Is there away to fix this?

I tried using the event structure and keydown event but can only read one key at a time.



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Message 8 of 9

There is no way that you can press multiple buttons at exactly the same time. Which keys are you trying to press? Are you talking about "PlatMods" (shift, ctrl, etc.)?


Keep a shift registers with the states of the desired buttons in a boolean array and change the respective elements to true or false, depending on key-up and key-down events. On the Key down events, check if all elements are true and act accordingly.

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Message 9 of 9