Key down event handeling when the VI isn't active

Hi
I've written a simplel VI that increases or decreases a numerical indicator depending on which key is pressed on the keyboard. But this only works when the VI window is active (the titlebar is blue and not gray). Is there anyway to listen for the key-down event even though the VI is not active?
In advance thanks
Georg

I recently ran into a problem with the Acquire Data.
See http://forums.ni.com/ni/board/message?board.id=170&message.id=147363
Just in case....

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When is Key down event case triggered

Hi all,
In event structure there is an event <this VI> key Down?
When will this event be triggered... i.e will this event be triggered only in case of a keyboard entry... ?
Or in case i use a barcode reader, if data gets populated in a control on the Front panel through the barcode reader will this trigger this event...?
Thanks

The Key Down event will only be fired when a key is pressed on the keyboard. If you want to fire an event off of a Front panel control, you can either use a User Event or a property node called Value (Signaling). This property node will cause a Value Change event to trigger when the value of the Front panel control changes.
Cheers

Key down event in background

Is there a way to make the key down event in the wait event structure run in the background when labview is not the focus? Also what is the difference between the "key down? event" and the "key down event"? I couldn't find a good answer in the LabVIEW help.

tst wrote:
To expand a bit on RF's answer, while you can't use the event structure to register for key down events in other windows, there are some potential options:
You could use the input VIs to poll the keyboard (and you can have a loop which will use a user event to send each new key to an event structure). The main problem with this (and it's a big one) is that it is unreliable. You would have to poll quickly enough (probably at ~20-50 Hz) to have a decent chance of being sure that you're not missing keys and even then it's not guaranteed. The other problem is that you don't know which window was actually in focus.
You could try getting the window messages from the other window. I have no real experience with Windows messaging, but my understanding is that this will probably require you to write a custom hook in C to get it, but it's possible that this is also possible with the standard Win32 API functions. Even if it is, this is probably not something you want to get into to, but you could try looking it up.
Actually this Windows Messaging already exists in LabVIEW:
http://zone.ni.com/devzone/cda/epd/p/id/4394
However there is a few issues. It only partially works in Windows 64-bit, and you have to know the handle to the application that you want to intercept key downs for. I did a quick test and I was able to detect the KEYDOWN event in another VI that was running for for some reason got an error when I tried to get keydown on notepad. This method would eliminate polling if you can get it to work, and because of this you shouldn't miss any key presses.
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If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.

Detecting external keyboard Key Down Events in Ipad2 without EditText Field.

I am trying to detect key pressed for an external keyboard (bluetooth) in IPad2 , I was only able to do so when the focus is on EditText Field.
Without the edit text field , the key down events are not captured by the program . Is there any work around for this issue .

I am trying to detect key pressed for an external keyboard (bluetooth) in IPad2 , I was only able to do so when the focus is on EditText Field.
Without the edit text field , the key down events are not captured by the program . Is there any work around for this issue .

How to separate "Key down" event from panel and numerical control

Hi, All
I have a vi proecess key down events for panel and a numerical control in this panel. the application will do:
1. when panel is focused, user can use "up" and "down" key to driver some hardware.
2. when the numerical control has the focus, "up" and "down" key will change it's value as usual.
somehow the second one did not work, because the panel "key down" event was trigger as well when I use "up' "down" key inise the numerical control.
then I used "Key down?" of numerical control to block the "up/down" key. But the first time when I run the Vi, the panel still got triggered one time.
any suggestions on this? test code attached in this post too.
thanks
CQ
Solved!
Go to Solution.
Attachments:
KeyDown_Up_valuechange.vi ‏16 KB

This works for me in 2014. In short, you just need to check to see if your numeric has the focus. If it doesn't, then you process the key value. No need for any other event here except for the stop button.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines
Attachments:
KeyDown_Up_valuechange_BD.png ‏32 KB

Key down events

Hi,
I've been working on code for handling a flash-plugin inside an existing application, and have been looking at getting the flash player working with the Cocoa/CoreGraphics API.
Thus far, I have plugin loading, focus, mouse handling events all working. But then key events don't work consistently - on some flash applications, the key down events work, but on most they return a '1' but the flash app doesn't respond.
This is most odd, and a pretty esoteric type of work - I don't know many people who get this kind of work, and it's hard finding people who can share their experiences of this.
I've been going through the NPAPI docs on the mozilla website and copying a lot of the handling code in WebKit, Chromium and Firefox, but none of it seems to help any more - my handling code works the same way as that does, but the responses for key down events are different.
So, this is just a last try before I go crazy - has anyone ever seen anything like this before?
Thanks,
Tom.

Well, it is a problem with Flash Player and not Flash. I don't need an experienced Flash developer.
Seriously though, the nature of the question is so esoteric that I doubt there are many developers anywhere who could give much advice.
Thanks anyway.

CS3/MAC key down events

I have a plugin which presents a dialog and does some keyboard input,
and under mac/cs3 ONLY, indesign is capturing and acting upon key
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Oddly, key UP events are being passed through normally.
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mac toolbox function WaitNextEvent.
Is this a known problem?

The last time I read about the Mac event manager, WaitNextEvent was deprecated in favour of carbon events. Maybe InDesign now also follows this path.
http://developer.apple.com/documentation/Carbon/Conceptual/Carbon_Event_Manager/Concept/ch apter_2_section_4.html
Anyway, bypassing InDesign in order to invoke WNE is bad style. Make yourself familiar with IEventHandler and alike.
> Is this a known problem?
If you're working at Extensis then at least one of your users now has found the problem ... . Could be a different reason though, I just saw this post:
Jeremy Paine, "ID CS3 Control Palette Oddity" #10, 17 Sep 2007 8:33 pm
Dirk

InsertionPalette activex control key down event

Hi,
Can any one know how to get the key down event of InsertionPalette activex control.
I have handled the KeyDownEvent but it is not fired while the control is active and key is pressed.
regards,
Ceaser

Ceaser,
what is the application developement environment you are working with?
Norbert
CEO: What exactly is stopping us from doing this?
Expert: Geometry
Marketing Manager: Just ignore it.

[svn:osmf:] 14007: Partial fix for FM-383: ProxyElement needs to dispatch traitRemove/ traitAdd event pairs when the proxy adds or removes a trait that also exists on the proxied element .

Revision: 14007
Revision: 14007
Author:   [email protected]
Date:     2010-02-05 11:54:43 -0800 (Fri, 05 Feb 2010)
Log Message:
Partial fix for FM-383: ProxyElement needs to dispatch traitRemove/traitAdd event pairs when the proxy adds or removes a trait that also exists on the proxied element.
Ticket Links:
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    osmf/trunk/framework/OSMF/org/osmf/proxies/ProxyElement.as
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Revision: 11448
Author:   [email protected]
Date:     2009-11-04 17:06:22 -0800 (Wed, 04 Nov 2009)
Log Message:
Making a small ItemRenderer change so that we don't dispatch an unused, contentBackgroundColorChanged event anymore when the itemIndex gets set.
QE notes: -
Doc notes: -
Bugs: -
Reviewer: Deepa
Tests run: checkintests
Is noteworthy for integration: No
Modified Paths:
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Revision: 11448
Author:   [email protected]
Date:     2009-11-04 17:06:22 -0800 (Wed, 04 Nov 2009)
Log Message:
Making a small ItemRenderer change so that we don't dispatch an unused, contentBackgroundColorChanged event anymore when the itemIndex gets set.
QE notes: -
Doc notes: -
Bugs: -
Reviewer: Deepa
Tests run: checkintests
Is noteworthy for integration: No
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Delete memory Id when the session is still active

Hi all,
Can anyone tell me how to clear the Memory Id when the session is still active.
I am getting the amount value through Memory Id from import and export parameter when I am posting the check. Again if I reprint the check without closing the session the amount value is getting double evertimes.
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Yathish

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Message was edited by:
Someneni

TS3694 What happens when the iPhone needs an activation and it doesn't respond? Then it asks me to restore it but due to an unknown error (-1) the iPhone can't be restored.

What happens when the iPhone needs an activation and it doesn't respond? Then it asks me to restore it but due to an unknown error (-1) the iPhone can't be restored.

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Key down event to start something an stop arbirtrary

hallo,
what I'm trying to do is to start an event on key down an do a loop , something like move an axis for CNC , and this until i press an arbitrary key again.
i have already a while loop an an event structure so it would be good just to add something withtout large modifications.
have anyone an example code for me , please.
i've looked already in a lots of posts but i can't find anything usefull for me.
many thanks in advance

again - lots of ways to do this.
The attached example is just the fastest I could modify the previous version
2006 Ultimate LabVIEW G-eek.
Attachments:
keydownvi3.vi ‏53 KB

Key down event handeling when the VI isn't active

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