Hi,
Currently, the axis does not expose this information, however, we just modified the code of the control so the next release will give more access to the generated timeline.
With the new version you'll be able to check if a date time is working or not using:
NTimeline timeline = chart.Axis(StandardAxis.PrimaryX).Scale.Timeline;
timeline.IsEmptyAt(someDateTime);
We expect to release a new version of .NET Vision next week. We hope this helps - let us know if you have any questions.
Best Regards,
Nevron Support Team