LabVIEW
How do I prevent an event structure from unbundling a cluster?
I have noticed recently that an event structure unbundles any cluster passed to it.
Does anyone know how to prevent this?
My workaround is to double wrap my cluster or re-bundle it before passing it into a vi.
My clusters have 20-30 elements.
Thanks in advance.
Note: While typing this up I see that others have provided good answers, but here is mine anyway ...
Although Timmar did not explicitly say it, I think the point that he is trying to make is that “User Event clusters” are handled differently than “front panel clusters” by the event structure. This variation in functionality requires that he make code changes that he would like to avoid.
For example, an “error in” cluster from the front panel, when used in a Value Change Event, goes in as a cluster and comes out as a cluster.
The same “error in” cluster from a User Event goes in as a cluster and comes out as an unbundled cluster. (See Timmar’s example.)
Issues that are caused by the functionality:
- To send an incoming cluster of 20 elements or more to a subvi – you would have to re-bundle the elements
- A large number of elements will cover the entire left side (or more) of the event
The work around is not too difficult.
When you create the User Event, pre-bundle your cluster by putting it in a cluster container with the same name.
When you generate the event, bundle the cluster.
I don’t think there is a way to prevent this behavior and this could be considered a feature. In the common use case where you are getting a User Event from a producer loop and want to send the data to several front panel indicators, the automatic unbundling saves you a step. Maybe that’s why NI did it this way.
My current project uses ~60 User Events. About half of them are “pre-bundled” as described here.
steve
