Class Property Node Failure when in LVLIB

[K-node]

So, as my development normally goes, I end up refactoring the file and library structures in preparation for a cleaner release. Frequently (um, always), I break something and sometimes LabVIEW breaks something.

Yesterday, I spent too many hours on a problem that caused LabVIEW to terminate unexpectedly and without warning or go into a hung state where task manager came to the rescue. In the end, the 'block' that caused my problem was setting two properties on a class using the Class Property Node capability in LV2010. I am using SP1. It seems that executing that function 'confused' LV. This approach was working until I made organizational changes to file locations and project libraries. I am pretty sure that this was the only place I used a Write property node where the class was inside a library (just an lvlib not packed). It could be that all I had to do was to remove the property node and add it again, but I was so frustrated by this problem that I got rid of class properties completely.

When I finally realized where it died, I kind of remember reading about a problem like this on LAVA. I recall AQ indicating he was disappointed in how testing of this release missed this error. I cannot find that post though.

Does anyone remember this? AQ, am I putting words in your post?

[jgcode]

I had a similar issue whereby after refactoring (I encapsulated part of the class into a Parent class for reuse) the PN caused a crash in the Run-Time but not Dev Environment. I ended up removing all Properties and staying clear of them. However, I like the new feature as it created a much cleaner BD.

[Jon Kokott]

class property nodes are broken pre sp1 for LV2010, and I haven't tested if they fixed the issue for sp1 yet, though it is supposed to be.

Here is a thread where I pretty much describe the same issue (LV crashing) there was a CAR assigned at some point.

http://lavag.org/top...nodes-and-dvrs/

255982

ReturnChild Class Property Node does not output until deleting and rewiring any part of the VI

This issue pertains to Object-Oriented Programming in LabVIEW. Essentially upon creating a Parent class and Child class, we are unable to read the child class properties in the main VI through property nodes unless we have changed the VI recently (i.e. unwire & rewire).

Workaround: The workaround for this issue is to use subVIs created from 'VI for Dynamic Dispatch Template.' Within the subVIs you are able to unbundle and bundle the object.

Reported Version: 2010 32-bit Resolved Version: 2010 SP1 32-bit Added:12/31/2010

Edited March 8, 2011 by Jon Kokott

[Mr Mike]

kugr, I'm not sure I follow your post entirely. However, an integral part of the fix for that CAR in 2010 SP1 requires you to recompile any VIs that use class property nodes. Deleting and replacing the property nodes would have caused it to recompile. If you can still reproduce the issue, please post your exact steps.

I'm sorry that my features caused you so much frustration. Me right now -->

[K-node]

kugr, I'm not sure I follow your post entirely. However, an integral part of the fix for that CAR in 2010 SP1 requires you to recompile any VIs that use class property nodes. Deleting and replacing the property nodes would have caused it to recompile. If you can still reproduce the issue, please post your exact steps.

I'm sorry that my features caused you so much frustration. Me right now -->

Thanks Mr Mike, Jon and JG.

There is no way I can reproduce what I did. I moved a lot of files around and rearranged classes in a variety of new and existing libraries.

Today I did put the Property capability back into the class that had the problem and used the Property Node in the VI was the last to execute before LabVIEW tanked. Not surprisingly, LV handled it this time.

-kugr