Custom series are represented by the NCustomSeries type. An instance of this type must be added to the series collection of a Cartesian, Polar or Radar chart.

// obtain a reference to the Cartesian chart that is created by default
NCartesianChart chart = (NCartesianChart)chartControl.Charts[0];

// add a custom series
NCustomSeries customSeries = new NCustomSeries();
chart.Series.Add(customSeries);

' obtain a reference to the Cartesian chart that is created by default
Dim chart As NCartesianChart = chartControl.Charts(0)

' add a custom series
Dim customSeries As NCustomSeries = New NCustomSeries
chart.Series.Add(customSeries)

A custom series has no associated data. It displays user painted graphics directly without additional processing. The painting is realized with the help of a callback interface called INCustomSeriesCallback. This interface must be implement by some type, for example:

class MyCustomSeriesCallback : INCustomSeriesCallback
{
    public void GetAxisRanges(out NRange1DD rangeX, out NRange1DD rangeY)
    {
        rangeX = new NRange1DD(0, 10);
        rangeY = new NRange1DD(0, 100);
    }
    public void Paint2D(NChartRenderingContext2D context, NGraphics graphics)
    {
        // TODO: paint with the graphics object here
    }
}

Public Class MyCustomSeries
    Implements INCustomSeriesCallback
    Public Sub GetAxisRanges(ByRef rangeX As NRange1DD, ByRef rangeY As NRange1DD) Implements _
        INCustomSeriesCallback.GetAxisRanges
        rangeX = New NRange1DD(0, 10)
        rangeY = New NRange1DD(0, 100)
    End Sub

    Public Sub Paint2D(ByVal context As NChartRenderingContext2D, ByVal graphics As NGraphics) Implements _
        INCustomSeriesCallback.Paint2D
        ' TODO: paint with the graphics object here
    End Sub
End Class

An instance of the implementing type must be assigned to the Callback property of the NCustomSeries object:

customSeries.Callback = new MyCustomSeriesCallback();

customSeries.Callback = New MyCustomSeriesCallback()

The INCustomSeriesCallback interface allows for the series to specify its content range, so that the chart axes are scaled appropriately. For this purpose in the GetAxisRanges method you have to set the actual ranges (in logical coordinates) of the custom series along the X and Y dimensions.

Windows forms: Chart Gallery\Custom\Custom Series