Drilling down data to get in to the details and access lower levels in data hierarchy of Sunburst chart can be quite helpful while analysis. Sunburst chart provides Drilldown property to enable the functionality of drilling down and drilling back up the data at runtime. 

End users can focus and drill down a data item in a Sunburst chart by simply clicking the desired slice. Whereas, to move up in the hierarchy, users simply need to right-click on a slice.

The following gif image demonstrates drilling-down by showing data points of the clicked Sunburst slice.

The following code showcases how to implement drill down feature in charts. This example uses the data used in the Quick Start topic.

<c1:C1Sunburst x:Name="sunburst" Drilldown="True" Binding="Value" BindingName="Year,Quarter,Month"
               ToolTip="{x:Null}" InnerRadius="0.2" ChildItemsPath="Items" Grid.Row="1">
    <c1:C1Sunburst.DataLabel>
        <c1:PieDataLabel Content="{}{name}" Position="Center"/>
    </c1:C1Sunburst.DataLabel>
</c1:C1Sunburst>