Hi,
At this point the area border is either displayed around the whole area or is not displayed at all. There is no way to make it show only at the top side of the area.
The option to use a line series is still quite possible. The problems that you pointed out can be solved with a few settings:
1) it colors the line differently than the area
You can change the border of the line series through the BorderStyle property of the series. It is also possible to change the color of each line segment individually if this is required.
lineSeries.BorderStyle.Color = Color.Red;
2) it adds extra legend entries.
you can disable the series legend item with the following code:
lineSeries.Legend.Mode = SeriesLegendMode.None;
Best Regards,
Nevron Support Team