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VBScript EasyDAClient event hooking without WScript

26 Sep 2022 15:10 #11118 by nknox

Thank you for pointing me in the direction of this resource and your explanation. Based on my research of CA Plex, it looks like it only supports hooking it's own physical events. So I believe that the Event Pull Mechanism will be the way to do this. Thanks again!
The following user(s) said Thank You: support

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21 Sep 2022 11:21 #11108 by support

How the events are hooked depends on the VBScript host; and unfortunately I do not know CA Plex. If you do not find a way to hook events, there is a workaround using QuickOPC's Event Pull Mechanism:


Internally there is still an OPC subscription and all works the same. Only the event delivery mechanism is different - instead of an event handler in your code being called, you pull the events from a queue, and process them in a loop.

There are VBScript example for this approach in the documentation as well.

I hope this helps.

Best regards

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20 Sep 2022 20:53 #11106 by nknox

I have a customer who is trying to upgrade a deprecated OCX control and is looking at OPC Data Client's COM development capabilities to do so. They are attempting to write a script for software they are using (CA Plex) based on the SubscribeItem example. Since it doesn't include Wscript, we are unsure how to navigate configuring the ItemChanged event hooking as function pointers do not seem to be supported in VBScript outside of GetRef(), which can only connect to DHTML events. Can you think of a way to work around this? Any guidance would be appreciated.

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