ValueQuery Methods
The ValueQuery object is used to setup and execute current value queries for CVS services. It is designed to be used with other queries that have obtained a tag list, such as the PointFacQuery.
Despite the method names, this query doesn’t provide a full-featured query engine that utilizes filters. It is, however, modeled like the other CxEventIF queries, with an asynchronous thread that can be created, started, polled, and canceled. Once the value filtering has begun, one does not need to wait for a notification to begin polling. The value entries are retrieved synchronously as they are requested.
Once the thread has been started, current values can be retrieved using point tags.
Declare the object using the following code:
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CreateObject("CxEventIf.ValueQuery") |
Each method in this document will assume you have declared the ValueQuery object using the following code:
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Dim ValueQuery Set ValueQuery = CreateObject("CxEventIf.ValueQuery") |
More:
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