If you look at screenshot, ProcessBook gives me a message if a number of pairs > 10000 on XY Trend.
I need to get this number using ActiveView component in C#. The reason of that is to give a message to user that "too many points..., please decrease range etc", otherwise the XYtrend will be displayed with "NO Data" - that is not true, there are more than enough data but the limit of pairs is 10 000.
Unfortunately, Pairs.Count only returns non-zero after the XYPlot has been painted (which would be after the user clicked OK and exited the Define dialog. This is written up internally as a known bug, but has not been scheduled for any release (yet).