An array of Int32 values that are the indexes of data points shown in the secondary chart.
If the ChartView.SplitType property is set to Custom, use the SecondPiePoints property to specify which data points should be displayed in the secondary chart of a Pie of Pie or Bar of Pie chart type.
By default, all data points in a series are numbered in the order they appear on a worksheet, starting from 0 (as shown in the image below). Determine the indexes of data points you wish to show in the secondary chart and set them to the SecondPiePoints property. As a result, you can completely control which data points will appear in the additional chart.
Currently, the SpeadsheetControl does not display the Pie of Pie or Bar of Pie chart types. However, they can be loaded and stored in supported formats, and you can create and modify them programmatically.