EventData is a Read-Only property that returns an object or data associated with the PIEventObject. The property is returned as a Variant.
The object placeholder is an object expression that evaluates to a PIEventObject object.
PIEventObject properties are dependent on the EventPipe source. For example, when retrieving an update from a PIPoint.Data.EventPipe the EventData property will contain a PointValue object with the update value. See the PIEventObject for details.