How to keep labels at multiples of e.g. 5 for a scrolling chart

Question

I have a winforms chart which is bound to a List. Every two seconds a new measurement is added to the list. My program is zooming to a 25 second interval and then scrolling to the end of the chart. I would like the x-axis to show multiples of 5 (5, 10, 15, 20...).

In the beginning it works fine, but then when the chart grows bigger and scrolling begins the labels, ticks and gridlines shift (eg 23, 28, 33, 38...).

How do I change this so it shows 25, 30, 35, 40... instead?

Here is my code for the chart:

chartArea1.AxisX.LabelStyle.Interval = 5D;
chartArea1.AxisX.MajorGrid.Interval = 5D;
chartArea1.AxisX.MajorTickMark.Interval = 5D;
chartArea1.AxisX.Minimum = 0D;
chartArea1.AxisX.MinorGrid.Interval = 5D;
chartArea1.AxisX.ScaleView.Position = 0D;
chartArea1.AxisX.ScaleView.Size = 25D;
chartArea1.AxisX.ScrollBar.Enabled = false;
chartArea1.AxisX.Title = "Time [s]";
chartArea1.AxisY.Interval = 20D;
chartArea1.AxisY.Title = "Cold pump\\nVol. [ml]";
chartArea1.Name = "ChartColdPump";
chartArea1.Position.Auto = false;
chartArea1.Position.Height = 25F;
chartArea1.Position.Width = 99F;

And the code for the scrolling, called each time a new measurement is added to the list:

componentsChart.ChartAreas[0].AxisX.ScaleView.Scroll(ScrollType.Last);

Answer 1

You need to adapt the various interval offsets to keep the labels at multiples of 5 or any other Interval you want.

Here is an example:

Axis ax = componentsChart.ChartAreas[0].AxisX; ;

ax.ScaleView.Scroll(ScrollType.Last);

int i1     = (int)ax.ScaleView.Position - 1;  // by default labels start at 1
int mult   = (int)ax.LabelStyle.Interval;
int offset = i1 % mult  == 0 ? 0 : mult  - (i1 % mult );

ax.IntervalOffset = offset;
ax.MajorGrid.IntervalOffset = offset;

Note that the default label start is at 1 ; you override it by setting a Minimum but after scrolling this no longer holds. So we need an offset to shift the intervals by the right amount..