CustomAggregateFunction Class

The base class for a custom aggregate function callback.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v18.1.dll

Declaration

C#

public abstract class CustomAggregateFunction :
    ICustomAggregateFunction

VB.NET

Public MustInherit Class CustomAggregateFunction
    Implements ICustomAggregateFunction

Related API Members

The following members accept/return CustomAggregateFunction objects:

• RadarSeriesViewBase.CustomAggregateFunction
• ScaleGridOptionsBase.CustomAggregateFunction
• XYDiagram2DSeriesViewBase.CustomAggregateFunction
• XYDiagram3DSeriesViewBase.CustomAggregateFunction

Example

Set the CustomAggregateFunction class descendant object to the ScaleGridOptionsBase.CustomAggregateFunction property to use the custom aggregate function. Note that the ScaleGridOptionsBase.AggregateFunction property should be set to Custom.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-implement-a-custom-aggregate-function-t625114

Form1.cs

private void Form1_Load(object sender, EventArgs e) {
    Series series = chartControl.Series["Random Data"];
    series.DataSource = GenerateData(100_000);
    series.ArgumentDataMember = "Argument";
    series.ValueDataMembers.AddRange("Value", "Value", "Value", "Value");

    XYDiagram diagram = chartControl.Diagram as XYDiagram;
    diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Custom;
    diagram.AxisX.DateTimeScaleOptions.CustomAggregateFunction = new OhlcAggregateFunction();
}

class OhlcAggregateFunction : CustomAggregateFunction {
    public override double[] Calculate(GroupInfo groupInfo) {
        double open = groupInfo.Values1.First();
        double close = groupInfo.Values1.Last();
        double high = Double.MinValue;
        double low = Double.MaxValue;
        foreach (double value in groupInfo.Values1) {
            if (high < value) high = value;
            if (low > value) low = value;
        }

        return new double[] { high, low, open, close };
    }
}

Form1.vb

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim series As Series = chartControl.Series("Random Data")
    series.DataSource = GenerateData(100_000)
    series.ArgumentDataMember = "Argument"
    series.ValueDataMembers.AddRange("Value", "Value", "Value", "Value")

    Dim diagram As XYDiagram = TryCast(chartControl.Diagram, XYDiagram)
    diagram.AxisX.DateTimeScaleOptions.AggregateFunction = AggregateFunction.Custom
    diagram.AxisX.DateTimeScaleOptions.CustomAggregateFunction = New OhlcAggregateFunction()
End Sub

Private Class OhlcAggregateFunction
    Inherits CustomAggregateFunction

    Public Overrides Function Calculate(ByVal groupInfo As GroupInfo) As Double()
        Dim open As Double = groupInfo.Values1.First()
        Dim close As Double = groupInfo.Values1.Last()
        Dim high As Double = Double.MinValue
        Dim low As Double = Double.MaxValue
        For Each value As Double In groupInfo.Values1
            If high < value Then
                high = value
            End If
            If low > value Then
                low = value
            End If
        Next value

        Return New Double() { high, low, open, close }
    End Function
End Class

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CustomAggregateFunction class.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

winforms-charts-implement-custom-aggregate-function/CS/DataAggregation/Form1.cs#L43

class OhlcAggregateFunction : CustomAggregateFunction {
    public override double[] Calculate(GroupInfo groupInfo) {

VB.NET

winforms-charts-implement-custom-aggregate-function/VB/DataAggregation/Form1.vb#L49

Private Class OhlcAggregateFunction
    Inherits CustomAggregateFunction

Inheritance

Object

CustomAggregateFunction