I'm trying to get a consistent stepline visualization of data consisting of a DateTime and a value. First, I tried the mapping like that:
That worked, but only as long as I didn't use zooming and scrolling - I always ended up with "No Data Series" for no obvious reasons - I guess the chart doesn't interpolate any missing values. This is bad and annoying. Try to explain a customer why he can't zoom into an area when he actually clearly sees that there IS data to see in an earlier zoom level.
When I changed the mapping from XValue to XCategory things got better, scrolling and zooming worked perfectly without ever showing me a "No Data Series". But there's another problem with that: the datasource consists of appr. 10.000 datapoints which I display with a samplingThreshold of 30. So in the first (unzoomed) view of the chart, no actual "real" data is shown, and all the dates resp. labels on the x-axis show the same datetime. When I zoom in several times until I dig down to the real data, where the sampling doesn't apply, the correct datetimes show up.
Although the latter way seems to be the more promising approach on the first look, it at the same time denies using multiple series in one chart, as the underlying data of the different series isn't temporally synchronized. So I would have to use an ItemMapping via XValue, but then zooming and scrolling doesn't work properly.
PS: I know that this strange behaviour is caused by the charts underlying filtering techniques for zooming and scrolling, and "technically" it may behave as expected - but from a user's point of view this behaviour is counter-intuitive and strange. It would be great if you could provide a solution for that dilemma.