Chart Area Zooming is a new 4.0 feature which allows a portion of a chart to be expanded into a secondary chart area which looks like the following:
This works by specifying a value range of a particular axis on the main chart area. Passing this information to the ChartArea.GetZoomAreaY() or GetZoomAreaX() methods will return a new chart area which doesn't need to be modified. When added to the Chart.ExtraChartAreas collection it will result in a chart area similar to the above.
ChartArea ca = Chart.ChartArea.GetXZoomChartArea(Chart.XAxis, new ScaleRange(new DateTime(2005,1,1),new DateTime(2006,1,1)),
Dim ca As ChartArea = Chart.ChartArea.GetXZoomChartArea(Chart.XAxis, New ScaleRange(New DateTime(2005, 1, 1), New DateTime(2006, 1, 1)),
New Line(Color.LightGreen, DashStyle.Dash))
This feature can be used in conjunction with the Axis Value Coordinates feature to allow the user to specify the range to zoom.
Axis Value Coordinates