[Obsolete("This method is obsolete now. Use the static RegisterGlobalSummaryFunction method instead.", false)]
public void RegisterSummaryFunction(
    string name,
    string displayName,
    ScaleType resultScaleType,
    int resultDimension,
    SummaryFunctionArgumentDescription[] argumentDescriptions,
    SummaryFunction function
)

<Obsolete("This method is obsolete now. Use the static RegisterGlobalSummaryFunction method instead.", False)>
Public Sub RegisterSummaryFunction(
    name As String,
    displayName As String,
    resultScaleType As ScaleType,
    resultDimension As Integer,
    argumentDescriptions As SummaryFunctionArgumentDescription(),
    function As SummaryFunction
)

Parameters

Type	Name	Description
String	name	A String value containing the function's name.
String	displayName	A String value containing the function's display name, which is used for localization purposes.
ScaleType	resultScaleType	A ScaleType enumeration value representing the type of the function's result.
Int32	resultDimension	An integer value representing the dimension of the resulting series point's values.
SummaryFunctionArgumentDescription[]	argumentDescriptions	An array of SummaryFunctionArgumentDescription objects containing argument descriptions.
SummaryFunction	function	A SummaryFunction delegate to be registered.

Remarks

The RegisterSummaryFunction method is intended to register custom summary functions within a chart control. To unregister a specific summary function, the XRChart.UnregisterSummaryFunction method should be called. Also, you may remove all custom summary functions from the chart, and add all default functions to it by calling the XRChart.ResetSummaryFunctions method.

Example

The following example demonstrates how to create a custom summary function, which returns a product of two values (Price * Count). To accomplish this task, it is required to create a summary function delegate and register it via the ChartControl.RegisterSummaryFunction method.

The code below illustrates how this can be done.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-register-and-use-a-custom-summary-function-t257050.

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Threading.Tasks
Imports System.Windows.Forms

Namespace RegisterSummaryFunctionExample
    Friend NotInheritable Class Program

        Private Sub New()
        End Sub

        ''' <summary>
        ''' The main entry point for the application.
        ''' </summary>
        <STAThread> _
        Shared Sub Main()
            Application.EnableVisualStyles()
            Application.SetCompatibleTextRenderingDefault(False)
            Application.Run(New Form1())
        End Sub
    End Class
End Namespace

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Windows.Forms
Imports DevExpress.XtraCharts

Namespace RegisterSummaryFunctionExample
    Partial Public Class Form1
        Inherits Form

        Private Const summaryFunctionName As String = "PRODUCT"

        ' Declare the Product summary function.
        Private Shared Function CalculateProductValue(ByVal series As Series, ByVal argument As Object, ByVal functionArguments() As String, ByVal values() As DataSourceValues, ByVal colors() As Object) As SeriesPoint()

            ' Create an array of the resulting series points.
            Dim points As New List(Of SeriesPoint)()
            ' Calculate the resulting series points as Price * Count.
            For i As Integer = 0 To values.Length - 1
                Dim value As Double = Convert.ToDouble(values(i)(functionArguments(0))) * Convert.ToDouble(values(i)(functionArguments(1)))
                If value > 0 Then
                    points.Add(New SeriesPoint(argument, value))
                End If
            Next i
            ' Return the result.
            Return points.ToArray()
        End Function

        Public Sub New()
            InitializeComponent()
            ' This line of code is generated by Data Source Configuration Wizard
            productsTableAdapter1.Fill(nwindDataSet1.Products)
        End Sub

        Private Function BuildSummaryFunction(ByVal price As String, ByVal count As String) As String
            Return (New StringBuilder(summaryFunctionName)).Append("([").Append(price).Append("],[").Append(count).Append("])").ToString()
        End Function

        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
            ' Register the summary function in a chart.
            chartControl1.RegisterSummaryFunction("PRODUCT", "PRODUCT", 1, New SummaryFunctionArgumentDescription() { _
                New SummaryFunctionArgumentDescription("Price", ScaleType.Numerical), _
                New SummaryFunctionArgumentDescription("Count", ScaleType.Numerical) _
            }, AddressOf CalculateProductValue)

            Dim series As Series = chartControl1.Series("Product")
            series.SummaryFunction = BuildSummaryFunction("UnitPrice", "UnitsOnOrder")
        End Sub
    End Class
End Namespace

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RegisterSummaryFunctionExample {
    static class Program {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main() {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using DevExpress.XtraCharts;

namespace RegisterSummaryFunctionExample {
    public partial class Form1 : Form {
        const string summaryFunctionName = "PRODUCT";

        // Declare the Product summary function.
        private static SeriesPoint[] CalculateProductValue(
            Series series,
            object argument,
            string[] functionArguments,
            DataSourceValues[] values,
            object[] colors) {

            // Create an array of the resulting series points.
            List<SeriesPoint> points = new List<SeriesPoint>();
            // Calculate the resulting series points as Price * Count.
            for (int i = 0; i < values.Length; i++) {
                double value = Convert.ToDouble(values[i][functionArguments[0]]) *
                    Convert.ToDouble(values[i][functionArguments[1]]);
                if (value > 0)
                    points.Add(new SeriesPoint(argument, value));
            }
            // Return the result.
            return points.ToArray();
        }

        public Form1() {
            InitializeComponent();
            // This line of code is generated by Data Source Configuration Wizard
            productsTableAdapter1.Fill(nwindDataSet1.Products);
        }

        String BuildSummaryFunction(String price, String count) {
            return
                new StringBuilder(summaryFunctionName)
                    .Append("([")
                    .Append(price)
                    .Append("],[")
                    .Append(count)
                    .Append("])")
                    .ToString();
        }

        private void Form1_Load(object sender, EventArgs e) {
            // Register the summary function in a chart.
            chartControl1.RegisterSummaryFunction("PRODUCT", "PRODUCT", 1,
                new SummaryFunctionArgumentDescription[] { 
                    new SummaryFunctionArgumentDescription("Price", ScaleType.Numerical), 
                    new SummaryFunctionArgumentDescription("Count", ScaleType.Numerical)},
                CalculateProductValue);

            Series series = chartControl1.Series["Product"];
            series.SummaryFunction = BuildSummaryFunction("UnitPrice", "UnitsOnOrder");
        }
    }
}