Why is there no Array of XControl in LabView8.6

[Jörn]

You can have a Cluster of XControls but not an array of an XControl.

Why can't Xcontrols placed in an array in LabView 8.6?

Is this changed in LV2009?

[smercurio_fc]

No, hasn't changed in LV2009. You may wish to post in the LabVIEW Idea Exchange.

[Ben]

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Jörn wrote:

You can have a Cluster of XControls but not an array of an XControl.

Why can't Xcontrols placed in an array in LabView 8.6?

...

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The following is just some speculation on my part.

Each instance of an XControl has a sepearte context created to handle each one ( I think of it as if I have written a dynamic VI and passed the control refs to it to hanld eth logic of each XControl). Since cluster are of fixed size LV can create the background stuff for each XControl when the VI containing them starts to run.

If I had an aray of XControls that was changing from empty to an array of a thousand etc there would be a very heavy hit to the CPU req's.

Ben

[Jörn]

hit to the CPU req's - not really. You don't need to keep copies of the facade VI and other stuff. Just the data need to be stored and that is not different to a cluster.

You need some copies of the XControl for the displayed part of the array elements. But these are few compared to an array of thousand elements.

[Intaris]

I recall hearing the opinion of an NI engineer on this.

All elements of an Array have identical properties but different data.  This allows for optimisations with the built-in data types in LV which is simply not possible with XControls.  An XControl could theoretically change its own properties and thus violate the "same properties" idea.

How far and why this might be important regarding the actual implementation is a bit beyond my knowledge of the internal workings of LV but I too would love to be able to make arrays of XControls.  Even if we had to watch problems like Facade size, display options and so on.

I know we can make an XControl which has an array as its data, but that's just not the same thing.  It also means duplicating code for a 1D array, a 2D array, a 3D array and so on.

So bottom line is that I think there are plenty of people who would like this, but I think it's either currently impossible for NI to implement or it's way down the list of future possibilities.

Shane.