This example demonstrates, integration between RadPivotGrid and RadCartesianChart and it uses the Cartesian chart's SeriesDescriptor to generate dynamic number of series and easily change between the series types. However, the pie chart is not part of the RadCartesianChart control and in order to change the chart's visualization you will need to use different control (The RadPieChart).
In order to use also a pie series type you can set a RadPieChart in the same container as the RadCartesianChart and when you change the SeriesType to Pie you can hide the Cartesian chart and show the pie chart, and vise verse.
For your convenience I prepared a sample project. Please give a try and let me know if it works for you.
Please let me know if you have any further questions.
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