To More Specific Class [Bug?]

[jgcode]

Is there anything wrong with this code or is it just me?

I think I am doing the same check however, with the GetLVClassDefaultValue.vi but it passes (but I expect it to fail).

Thoughts?

[Francois Normandin]

Hi Jon,

You typecast from LVObject to LVObject, so I'd expect that you don't get an error for that with "To More Specific Class" prim. I suspect there would be a significant increase in overhead if this primitive were to dynamically check for the class hierarchy when it's fed with LVObject. It seems to me that this is like a using the code below:

<a href="http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png"><img'>http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png"><img class="embeddedObject" src="http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png" width="452" height="249" border="0" /></a>

While the other case is clearly wrong as expected.

In my opinion, this is not a bug in the behavior of the primitive but perhaps a bug in documentation?

[jgcode]

Hi Jon,

You typecast from LVObject to LVObject, so I'd expect that you don't get an error for that with "To More Specific Class" prim. I suspect there would be a significant increase in overhead if this primitive were to dynamically check for the class hierarchy when it's fed with LVObject. It seems to me that this is like a using the code below:

<a href="http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png"><img'>http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png"><img class="embeddedObject" src="http://content.screencast.com/users/normandinf/folders/Jing/media/7a120e9c-2ed5-448a-973c-9971c69993b2/class%20typecast.png" width="452" height="249" border="0" /></a>

While the other case is clearly wrong as expected.

In my opinion, this is not a bug in the behavior of the primitive but perhaps a bug in documentation?

Thanks dude!

I want to run script that finds any member in Project that is a Child of Parent by Name/Ref (not static - so I can't use the constant).

Is there a better way to do this? - Given the above, I am thinking just looking at the Ancestor Paths for a match in path?

[Daklu]

I think I am doing the same check however, with the GetLVClassDefaultValue.vi but it passes (but I expect it to fail).

Like Francois said, the downcast prim is based on wire type, not object type. Try using the Preserve Run Time Class prim to get the behavior you expect.

[jgcode]

Like Francois said, the downcast prim is based on wire type, not object type. Try using the Preserve Run Time Class prim to get the behavior you expect.

[Aristos Queue]

What Daklu said.

[jgcode]

GDamnit, I suck

[Aristos Queue]

GDamnit, I suck

Hey! No taking G's name in vain! No wonder LabVIEW doesn't always work for you!