Trendline Interface

A trendline in a chart that shows trends in the series data.

Namespace: DevExpress.Spreadsheet.Charts

Assembly: DevExpress.Spreadsheet.v19.1.Core.dll

Declaration

C#

public interface Trendline :
    ShapeFormat,
    ShapeFormatBase

VB.NET

Public Interface Trendline
    Inherits ShapeFormat,
             ShapeFormatBase

Related API Members

The following members return Trendline objects:

• TrendlineCollection.Add(ChartTrendlineType, String)
• TrendlineCollection.Add(ChartTrendlineType)

Remarks

The Trendline object is contained within the TrendlineCollection collection. The Series.Trendlines property provides access to a collection that contains all trendlines for a specified series.

The following code uses the TrendlineCollection.Add method to display a trendline of the ChartTrendlineType.Polynomial type. The Trendline object in the collection is customized as required.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/spreadsheet-document-server-chart-api-t132724

TrendlineActions.cs

Worksheet worksheet = workbook.Worksheets["chartTask3"];
workbook.Worksheets.ActiveWorksheet = worksheet;

// Create a chart and specify its location.
Chart chart = worksheet.Charts.Add(ChartType.ScatterMarkers);
chart.SelectData(worksheet["C2:F3"], ChartDataDirection.Row);
chart.TopLeftCell = worksheet.Cells["H2"];
chart.BottomRightCell = worksheet.Cells["N14"];

// Set the minimum and maximum values for the chart value axis.
Axis axis = chart.PrimaryAxes[1];
axis.Scaling.AutoMax = false;
axis.Scaling.AutoMin = false;
axis.Scaling.Min = 0.6;
axis.Scaling.Max = 1.0;
chart.PrimaryAxes[1].MajorGridlines.Visible = false;

// Display a polynomial trendline.
chart.Series[0].Trendlines.Add(ChartTrendlineType.Polynomial);

// Customize the trendline.
Trendline tline = chart.Series[0].Trendlines[0];
tline.DisplayEquation = true;
tline.CustomName = "Trend";
tline.DisplayRSquare = true;
tline.Backward = 1;
tline.Forward = 2;
tline.Outline.SetSolidFill(Color.Red);

TrendlineActions.vb

Dim worksheet As Worksheet = workbook.Worksheets("chartTask3")
workbook.Worksheets.ActiveWorksheet = worksheet

' Create a chart and specify its location.
Dim chart As Chart = worksheet.Charts.Add(ChartType.ScatterMarkers)
chart.SelectData(worksheet("C2:F3"), ChartDataDirection.Row)
chart.TopLeftCell = worksheet.Cells("H2")
chart.BottomRightCell = worksheet.Cells("N14")

' Set the minimum and maximum values for the chart value axis.
Dim axis As Axis = chart.PrimaryAxes(1)
axis.Scaling.AutoMax = False
axis.Scaling.AutoMin = False
axis.Scaling.Min = 0.6
axis.Scaling.Max = 1.0
chart.PrimaryAxes(1).MajorGridlines.Visible = False

' Display a polynomial trendline.
chart.Series(0).Trendlines.Add(ChartTrendlineType.Polynomial)

' Customize the trendline.
Dim tline As Trendline = chart.Series(0).Trendlines(0)
tline.DisplayEquation = True
tline.CustomName = "Trend"
tline.DisplayRSquare = True
tline.Backward = 1
tline.Forward = 2
tline.Outline.SetSolidFill(Color.Red)

The resulting chart is shown in the following picture.