General ActiveX Questions

[sal]

Hi,
I have some general ActiveX questions I hope somebody can answer for me. (I mistakenly just posted this in the DSC forum!!)

1. What happens if you register an activex control twice? Anything? How do you know if an ActiveX control is registered?


2. If I place an ActiveX control on my front panel via the activex container, is there a way I can tell from which .ocx file the control originates?


3. For a simple menu vi where you are waiting on the operator to make a button selection (which normally you are polling in a loop), is there a performance difference between using the new event features of Labview 6.1 and using ActiveX controls on the front panel and using the ActiveX event vi's?


Thanks for the help

[Greg_McKaskle2]

> 1. What happens if you register an activex control twice? Anything?
> How do you know if an ActiveX control is registered?
>


I am not 100% sure, but I suspect that this does no harm. I'm sure that
I've done it in the past.

>
> 2. If I place an ActiveX control on my front panel via the activex
> container, is there a way I can tell from which .ocx file the control
> originates?
>


Some controls have an About tab in their properties, it may be listed
there.

>
> 3. For a simple menu vi where you are waiting on the operator to make
> a button selection (which normally you are polling in a loop), is
> there a performance difference between using the new event features of
> Labview 6.1 and using ActiveX controls on the front panel and using
> the Act
iveX event vi's?
>


I'm pretty sure that the LV buttons are more efficient in LV, even when
polled with a reasonable delay. The ActiveX events actually have lots
of work to do in order to get to a diagram.

As I'm running on a Mac right now, I can't test these for sure, but it
should be simple to make a simple test VI to measure the overhead. You
might want to up the sample rate on the Performance Monitor, assuming
you are using NT or similar OS, and let the spikes indicate the
overhead. You can integrate by eye and see which is more efficient.
Another way might be to make the diagram count clicks per second and you
pretend to be playing a video game with your mouse. See how many of the
rapid clicks you can catch.

Greg McKaskle