BeforeQuery Event
From Microsoft Office Web Components Object Model
BeforeQuery Event
Occurs when the PivotTable list queries its data source.
Private Sub Object_BeforeQuery()
Object The name of the PivotTable object that you are trapping this event for.
Remarks
This event occurs quite frequently. Some examples of actions that trigger this event include adding fields to the PivotTable list, moving fields, sorting, or filtering data.