How do you set the line style for the Value Axis increment lines?
Thanks for your query.
See the sample code segment for your reference:
chart.ValueAxis.AxisLine.Color = Color.Maroon;
chart.ValueAxis.AxisLine.Style = LineType.Dot;
chart.ValueAxis.AxisLine.Weight = WeightType.WideLine;
You should check and browse different properties of Chart.ValueAxis.AxisLine for your needs.
Hope, this helps a bit.