This sample illustrates trackball feature in chart. To show trackball, hover or long press the chart and you can see the point value near to the mouse point.
This sample demonstrates the trackball behavior in chart. Trackball is used to track a data point closer to the current mouse position or touch contact point.
You can show tooltip for individual point or group of points closer to mouse position using
shared properties in tooltip.
Hover the chart area to view trackball and its tooltip. Touch and hold to enable trackball in touch enabled devices.
More information on the Tooltip and Trackball can be found in this documentation section.