event ViewChange ()
Occurs when the control's view is changed, such as when data is updated, summarized, sorted, or filtered.

TypeDescription
The ViewChange event is triggered whenever there is a change in the control's view. This can happen when the data is updated, summarized, sorted, or filtered, causing the control to display the modified information. To access the underlying data after such a change, the Data property of the CustomView can be used. The Data property of the CustomView can be used to access the data of the PivotTable, retrieving it as a two-dimensional safe array. The OleEvent occurs whenever the custom view control fires an event. The CustomView property retrieves the CustomView object of the pivot control, allowing you to redefine its display. The ViewChange event allows you to access and modify the custom view properties if a ControlID is specified. 

Once the ViewChange event occurs the following properties are updated:

Similarly, the internal eXGraph control is updated automatically based on this information. (only if the ControlID property is "exontrol.graph")

The following example shows how you can change the direction of the series (Vertical property of the Serie object) (only if the ControlID property is "exontrol.graph")

Private Sub Pivot1_ViewChange()
    With Pivot1.CustomView
        If Not .Object Is Nothing Then
            .Object.BeginUpdate
            With .Object.Series
                For i = 0 To .Count - 1
                    .Item(i).Vertical = True
                Next
            End With
            .Object.EndUpdate
        End If
    End With
End Sub

so they show as: