Event structure to detect value change of a control within a cluster in an array

I have 1D array that contains a cluster. The cluster contains a numeric and a boolean control.
If the user starts to edit the numeric control value i would like to call one subVI, and if the boolean control value is changed, call a different subVI.
The array control on the front panel allows the user to edit a number of the array elements.
I would like to use an event structure to detect a value change in the cluster. When editing the Events, in the Event Sources panel i get the option to select only the array, not the cluster within the array or the controls within the cluster. Can the Event structure be opened up to show controls within clusters and arrays?
The solution i am using is to detect a mouse up event on the array and then use property nodes to determine if the key focus is on the numeric, and a case structure to determine which subVI to call. This works, but is there a better (simpler) way?
Thanks, Blue.

Thanks for the responses guys.
The tricky bit was that i wanted the numeric control values to flag they were going to be edited, so i could call a subVI, before their values were changed by the user. This is done by using the key focus property node, - i need to detect changes on the fly rather than post the event. Probably didn't make this clear enough in my original post.
The array is of variable size depending on if the user decides to insert or delete elements. The user also has the option to click and edit the array without having to do to much scrolling through the array index, as the FP shows several elements at a time. The Event Structure does a good job of automatically determining which element in the array is being edited, and returning those values to the property nodes. Turned out simpler than i thought it might be at one point!
Cheers, Blue.
Message Edited by BlueTwo on 01-15-2009 06:52 AM
Attachments:
evstrct1.jpg ‏63 KB

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Changed.png ‏3 KB

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Attachments:
BooleanInCluster.png ‏11 KB

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In article <[email protected]>,
new_user wrote:
> Hi,
>
> Yes I will gladly post my VI.There are (2) block diagrams. The
> 'setpoint' ring controls should invoke the upper block diagram in the
> event of a selection.
> The lower block diagram should be invoked when the 'Initialize
> Displays' push button is pressed. It is turned off upon successful VI
> execution.
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sequence structure entirely it is not necessary to force a sequence on
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Solved!
Go to Solution.

This is a basic issue on which you can find tons of forum posts
The online help for the function recitates:
int SetCtrlVal (int panelHandle, int controlID, ...);
Parameters
Input
Name
Type
Description
panelHandle
int
Specifier for a particular panel that is currently in memory. You obtain this
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controlID
int
The defined constant, located in the .uir header file, that you assigned to the control in the User Interface Editor, or the ID returned by NewCtrl or DuplicateCtrl.
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New value of the control. The data type of value must match the data type of the control.
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int SetCtrlVal (int panelHandle, int controlID, ...);
Purpose
Sets the value of a control to a value you specify.
When you call SetCtrlVal on a list box or a ring control, SetCtrlVal
sets the current list item to the first item that has the value you
specify. To set the current list item through a zero-based index, use SetCtrlIndex.
When you call SetCtrlVal on a text box, SetCtrlVal appends value to the contents of the text box and scrolls the text box to display value. Use ResetTextBox to replace the contents of the text box with value.
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Parameters
Input
Name
Type
Description
panelHandle
int
Specifier for a particular panel that is currently in memory. You obtain this
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controlID
int
The defined constant, located in the .uir header file, that you assigned to the control in the User Interface Editor, or the ID returned by NewCtrl or DuplicateCtrl.
value
New value of the control. The data type of value must match the data type of the control.
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Message Edited by HaD on 08-06-2007 03:43 AM

Hi HaD,
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Message Edited by GerdW on 08-06-2007 11:21 AM
Best regards,
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Hi Cyle,
Please take a look at the document below. It explains why the events are not being fired.
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Intensive slider control use may lead to LabVIEW hang and system instability when coupled to event loop "Value Change"

Occasionally, over the past year or two, I have noticed on different machines and versions of LabVIEW (8.0 and 8.5) that intensive operation of the LabVIEW slider control (holding down the left mouse button and shaking the mouse quickly back and forth to move the slider for several seconds) may cause LabVIEW to hang with high CPU usage (50% on my current test machine, which has a Pentium IV "hyperthreaded" processor, so 50% is the max that a single thread can take up). In some instances, after the LabVIEW process is forced to quit, the system itself becomes unstable (more high CPU usage) or hangs, up to and including the need for a hard restart. I have seen this behavior both when handling slider change events the "old fashioned" way with a while loop and a case structure; and also when using a while loop with an event structure handling the "Value Change" event for the slider.
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Attachments:
Hang Slider.rtf ‏683 KB

Thanks for all your responses, and especially to those who are waggling their mice around trying to reproduce this. I'll respond to (most aspects of) the last several posts in one message.
LabViewGuruWannabe:
I'll see if I can get the original code to post in a separate message, I posted the .rtf originally because I thought there might be filtering on forum posts (I'm sort of new here). But I doubt you re-created it wrong.
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Huh, I never even noticed that checkbox existed. Anyway, yes, I
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Message Edited by dman on 02-04-2008 06:36 AM

Event structure buffering?

Hi all,
A quick question, if i have an event structure with lots of value change events for booleans, if 2 or 3 change at the same time or within a few milliseconds of each other does it buffer this event so that when it comes out of the event structure it knows another one has happened since it last went in? i.e. it could get a trigger for one, enter the event structure pass over a couple of ones that didnt trigger then get a trigger for them whilst its in it, but gone past them, then deal with the one that did trigger it and exit. Or perhaps i am not understanding how event structures process the value change triggers.
I hope i have explained myself well enough
Cheers
Mike

Pnt wrote:
Yes. As far as i know, events are buffering and it is NOT possible to miss one.
I agree here. You cannot "lose" any events. Sometimes this is a problem as demonstrated (and solved) in this old discussion:
http://forums.ni.com/ni/board/message?board.id=170&view=by_date_ascending&message.id=207811#M207811
Pnt wrote:
I agree that you should not have the same event in two different event cases (in parallel), but i disagree that there is possibility to miss an event.
LabVIEW will not allow you to place the same event in multiple event cases anyway, so there is no problem. However there is also no problem having two different event structures listening to the same event.
LabVIEW Champion . Do more with less code and in less time .

Event Structure's value change, not detecting changes when tabbing thru array of clusters

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Thanks!

mfitzsimons wrote:
altenbach
Tried Value Change with my example done in 7.1 and it doesn't trgger an event. That is why I suggested Mouse Down.
Curious. I did a few minor edits in 8.0 before saving as 7.1, but the simple value change event got triggered just fine when the value vas terminated with a tab in 7.1. Every time. Strange....
Are you on 7.1 or 7.1.1? Maybe there's a difference (I am using 7.1.1).
LabVIEW Champion . Do more with less code and in less time .

How to tackle the dataflow problem when Value Change event always triggers after another GUI event

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For example, in a mockup application that the grand purpose is to have user entered values in a textbox logged to a file (no missing information is accepted, and there is a boolean to determine how the information is logged).
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There are 3 problems when instead of clicking anywhere on the front panel after modifying text box B, the user ends up clicking on boolean control A.
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Now the situation I made up seems non-sense, but I believe it resembles one way or another a problem that you might run into. How would you solve this problem elegantly ?

You can set the string control to "update while typing".
Are you sure appending the log to itself is reasonable? Wouldn't it grow without bounds if the users keeps entering strings or pressing the ingore button?
Why isn't the "constant" a diagram constant instead of a control. Is the user allowed to change it?
To reset just write empty strings or a false to local variables of the controls (renit to defaults" seems a bit heavy handed).
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Event structure to detect value change of a control within a cluster in an array

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