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Syntax
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Point.OnChange
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Description
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To request the point's value on change. The next value of the point may be received by calling the
GetNext
method or function. The current value of the point is returned immediately. Any subsequent
GetNext
call will block until the point's value changes.
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Only one of the
OnChange
,
OnAlarm
,
OnTimed
or
OnAlarmAck
requests may be activate at a time.
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Example
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Read the point value on change forever.
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Sub main()
??????Dim MyPoint as new Point????????' Declare the point object
??????MyPoint.Id = "TANK_LEVEL"??????' Set the Id
??????MyPoint.OnChange????????????????????????' Request the value on change
top :
??????MyPoint. GetNext????????????????????????' Get the value
??????Trace MyPoint.Value??????????????????' trace it to the output window
??????goto top????????????????????????????????????????' repeat forever
end sub
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See also
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Point.GetNext (method); Point.OnTimed (method); Point.Cancel (method).
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CIMPLICITY
