The Line Series cannot be clicked/selected and cannot be used in DrillDown scenarios.
Hi Jared, can you please contact our support engineers via https://www.telerik.com/account/support-tickets, so they can help you achieve what you need.
I would also like to see the ability to drill down or an event fire when a point is clicked on a line series. I've combined my line series chart with a grid view and would like to filter the grid if a user clicks on a point.
RadChartView supports Hit testing only for data point elements. If you want to click/select or drill down you have to click on such a data point element. For all line series the default size of the data point elements is equal to SizeF.Empty. In order to allow users to click on data point elements you have to set the PointSize property to a value larger than SizeF.Empty.