SummaryFunctionArgumentDescription(String, ScaleType) Constructor

Initializes a new instance of the SummaryFunctionArgumentDescription class with the specified name and scale type.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v23.2.dll

NuGet Package: DevExpress.Charts

Declaration

C#

public SummaryFunctionArgumentDescription(
    string name,
    ScaleType scaleType
)

VB.NET

Public Sub New(
    name As String,
    scaleType As ScaleType
)

Parameters

Name	Type	Description
name	String	A String that specifies the name of the argument.
scaleType	ScaleType	A ScaleType enumeration value, which specifies the scale type for the function argument. For example, if the scale type is ScaleType.Numerical, only numerical fields will be shown for the Summarization function editor in the chart wizard.

Example

The following example demonstrates how to create a custom summary function, which returns an OHLC point calculated by the passed array of values. To accomplish this task, create a SummaryFunction delegate and register it using the ChartControl.RegisterSummaryFunction method:

C#

// Declare the Financial summary function. 
private static SeriesPoint[] CalculateProductValue( 
        Series series, 
        object argument, 
        string[] functionArguments, 
        DataSourceValues[] values, 
        object[] colors
) { 
    string functionArgument = functionArguments[0]; 
    int lastIndex = values.Length - 1; 

    double open = Convert.ToDouble(values[0][functionArgument], CultureInfo.InvariantCulture); 
    double close = Convert.ToDouble(values[lastIndex][functionArgument], CultureInfo.InvariantCulture); 
    double high = Math.Max(open, close); 
    double low = Math.Min(open, close); 
    for (int i = 1; i < lastIndex; i++) { 
        high = Math.Max(high, Convert.ToDouble(values[i][functionArgument], CultureInfo.InvariantCulture)); 
        low = Math.Min(low, Convert.ToDouble(values[i][functionArgument], CultureInfo.InvariantCulture)); 
    } 
    // Return the result. 
    return new SeriesPoint[] { 
        new SeriesPoint(argument, high, low, open, close) 
    }; 
} 

private void Form1_Load(object sender, EventArgs e) { 
    chartControl.DataSource = new CurrencyRateLoader("../../Data/EurUsdRate.xml").Load();
    // Register the summary function in a chart. 
    chartControl.RegisterSummaryFunction( 
            name: "FINANCIAL", 
            displayName: "Financial", 
            resultScaleType: ScaleType.Numerical, 
            resultDimension: 4, 
            argumentDescriptions: new SummaryFunctionArgumentDescription[] { 
                new SummaryFunctionArgumentDescription("Value", ScaleType.Numerical) 
            }, 
            function: CalculateProductValue
    );

    Series series = chartControl.Series["EurUsd"]; 
    series.ArgumentDataMember = "DateTime";
    // Note that ValueDataMembers are not specified.
    series.DateTimeSummaryOptions.SummaryFunction = "FINANCIAL([Value])"; 
}

VB.NET

' Declare the Financial 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()
    Dim functionArgument As String = functionArguments(0)
    Dim lastIndex As Integer = values.Length - 1

    Dim openValue As Double = Convert.ToDouble(values(0)(functionArgument), CultureInfo.InvariantCulture)
    Dim closeValue As Double = Convert.ToDouble(values(lastIndex)(functionArgument), CultureInfo.InvariantCulture)
    Dim highValue As Double = Math.Max(openValue, closeValue)
    Dim lowValue As Double = Math.Min(openValue, closeValue)
    For i As Integer = 1 To lastIndex - 1
        highValue = Math.Max(highValue, Convert.ToDouble(values(i)(functionArgument), CultureInfo.InvariantCulture))
        lowValue = Math.Min(lowValue, Convert.ToDouble(values(i)(functionArgument), CultureInfo.InvariantCulture))
    Next i
    ' Return the result.
    Return New SeriesPoint() { 
        New SeriesPoint(argument, high, low, open, close_Renamed) 
    }
End Function

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    chartControl.DataSource = (New CurrencyRateLoader("../../Data/EurUsdRate.xml")).Load()
    ' Register the summary function in a chart.
    chartControl.RegisterSummaryFunction(
            name:= "FINANCIAL", 
            displayName:= "Financial", 
            resultScaleType:= ScaleType.Numerical, 
            resultDimension:= 4, 
            argumentDescriptions:= New SummaryFunctionArgumentDescription() { 
                New SummaryFunctionArgumentDescription("Value", ScaleType.Numerical) 
            }, 
            [function]:= AddressOf CalculateProductValue
    )

    Dim series As Series = chartControl.Series("EurUsd")
    series.ArgumentDataMember = "DateTime"
    ' Note that ValueDataMembers are not specified.
    series.DateTimeSummaryOptions.SummaryFunction = "FINANCIAL([Value])"
End Sub