This event is generated when the user selects the Zoom out all button from the Toolbar or calls the SetZoomOutAll method. Use this event to perform operations before a zoom-out-all is performed, that is, before the chart is redrawn to the zoom-out-all state.
'XYChartCtl1 is the name of the XY Chart control instance placed on the form
Private Sub XYChartCtl1_ZoomOutAllSelected()
XYChartCtl1.Profile(1).SampleStep = 2 'Display every other value for Profile 1