How to handle event from subVI in the main VI?

Question

Hello,
I'm doing some measurement. During the measurement I want the user to see some activity dialog - that's easy to do. Before the measurement starts I dynamically run VI (EX_Progress.vi) that shows some activity and then I do the measurement (in my example simulated by random number generation) . After the measurement is done (or error occurs) I can dynamically abort the activity indicator. But on the other hand I want to give to the user chance to abort the measurement manually via the activity dialog by STOP button. There are some ways how to do it via global variable and check every iteration in the main VI it's state but isn't there some better way? Would be nice to run event in the main VI when the user pushes the STOP button in the Progress VI. Is it possible to achieve this using register events? I tried but don't really now how I'm not familiar with this technique.
Thanks in advance
Message Edited by ceties on 11-26-2007 01:34 PM
LV 2011, Win7
Attachments:
Ex.zip ‏374 KB

Answer 1

OK, here's an example using User Events. It doesn't directly have the main VI listen for the Button press event in the subVI. Instead, it has the main VI listen for a custom User Event that the subVI fires every time there's a button press. You could theoretically directly listen to the button press directly from the Main VI, but you would have to somehow get that control's reference to the main VI. That would require storing a copy of it in a global or some such method. This method I will show here is very common and is definitely worth learning.
For more info on User Events, refer to the LabVIEW help. You can learn more by clicking any of the User Event VIs and selecting Help from the shortcut menu.
(I didn't set the subVIs front panel to open automatically, so you'll have to do that yourself to see anything from this demo...)
Message Edited by Jarrod S. on 11-26-2007 02:51 PM
Jarrod S.
National Instruments
Attachments:
Example.zip ‏25 KB