As you may noticed RadChartView also doesn't support this kind of visualization (box plot) out of the box. However, you can achieve this effect using a CandlestickSeries with a PointTemplat that contains a custom shape that draws a custom geometry. For your convenience I attached a sample project demonstrating this approach. Please give it a try and let me know if it works for you.
In addition you can take a look at the Box Plot Series feature request in our feedback portal
where you can track the status of the feedback item.
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Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items