Thanks for your update. We have analyzed your requirements and we like to inform you that,
You can achieve your requirement using RangeArea Series as follows,
series.Type = ChartSeriesType.RangeArea;
series.Points.Add(-10, 30, 43);
series.Points.Add(0, 30, 50);
series.Points.Add(6, 30, 54);
series.Points.Add(20, 30, 54);
We have prepared a sample based on this. Please find the attached sample.
Please let us know if you have any concern.
Thanks for your update.
Please let us know if you have any further assistance.