I use the following code to create and display a line with some text at the line's midpoint. With SamplingMode enabled, the label does not appear. With SamplingMode disabled, it does. I would like to get some of the performance gains out of using SamplingMode, but is there a way to do it such that the label will show up?

private void DisplaySpectrum(SpectrumViewModel s)
{
var line = (NLineSeries)nccSpectra.Charts[0].Series.Add(SeriesType.Line);

line.Tag = s;
line.Name = s.Name;
line.UseXValues = true;
//line.SamplingMode = SeriesSamplingMode.Enabled;

line.DataLabelStyle.Visible = true;
line.DataLabelStyle.Format = "";
line.MarkerStyle.PointShape = PointShape.Cylinder;
line.MarkerStyle.Width = new NLength(1.5f, NRelativeUnit.ParentPercentage);
line.MarkerStyle.Height = new NLength(1.5f, NRelativeUnit.ParentPercentage);
line.BorderStyle.Color = s.Color;

var refs = s.References.Where(r => r.Displayed).ToArray();
string text = string.Empty;

if (refs.Count() > 0)
text = refs.Select(r => string.Format("{0} {1}: {2}", r.Name, r.MethodName, r.ValueAndUnit)).ToDelimString(Environment.NewLine);

var points = s.XAxisRow.Values.Zip(s.YAxisRow.Values, (x, y) => new DataPoint(x, y)).ToArray();
int midPoint = points.Length / 2;

for (int i = 0; i < points.Length; i++)
{
if (i == midPoint && !string.IsNullOrEmpty(text))
line.AddDataPoint(new NDataPoint(points[i].X, points[i].Y, text));
else
line.AddDataPoint(new NDataPoint(points[i].X, points[i].Y));
}

s.Line = line;
}

Hi John,

The easiest way to achieve is to have a second point scatter series for the data labels - for example:

   NChart chart = nChartControl1.Charts[0];

   NLineSeries line = new NLineSeries();
   line.SamplingMode = SeriesSamplingMode.Enabled;
   line.UseXValues = true;

   NPointSeries point = new NPointSeries();
   point.UseXValues = true;
   point.Size = new NLength(0);

   Random rand = new Random();

   for (int i = 0; i < 10000; i++)
   {
    double x = i;
    double y = Math.Sin(i / 1000.0);

    line.XValues.Add(x);
    line.Values.Add(y);

    if (i % 1000 == 0)
    {
     point.XValues.Add(x);
     point.Values.Add(y);
    }
   }

   chart.Series.Add(line);
   chart.Series.Add(point);

Creates a chart with two series - line series and a point series with zero size used only to show data labels. Hope this helps - let us know if you meet any problems or have any questions.

Best Regards,
Nevron Support Team