How to: Specify the Appearance of the Pie Chart Using Its Pattern at Runtime

• Nov 13, 2018
• 4 minutes to read

The following example demonstrates how to specify the appearance of series labels in the Pie chart using its text pattern.

To accomplish this at runtime, it is necessary to handle the Form.Load event and then transform series labels of the Series object to the corresponding labels of the PieSeriesLabel object.

And finally, specify the pattern for series labels using the SeriesLabelBase.TextPattern property.

View Example

Form1.cs

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

namespace Series_PieChart {
    public partial class Form1 : DevExpress.XtraEditors.XtraForm {
        public Form1() {
            InitializeComponent();
        }
        private void Form1_Load(object sender, EventArgs e) {
            // Create an empty chart.
            ChartControl pieChart = new ChartControl();

            pieChart.Titles.Add(new ChartTitle() { Text = "Land Area by Country" });

            // Create a pie series.
            Series series1 = new Series("Land Area by Country", ViewType.Pie);

            // Bind the series to data.
            series1.DataSource = DataPoint.GetDataPoints();
            series1.ArgumentDataMember = "Argument";
            series1.ValueDataMembers.AddRange(new string[] { "Value" });

            // Add the series to the chart.
            pieChart.Series.Add(series1);

            // Access diagram settings.
            SimpleDiagram diagram = (SimpleDiagram)pieChart.Diagram;
            diagram.Margins.All = 10;

            // Format the the series labels.
            series1.Label.TextPattern = "{VP:p0} ({V:.##}M km²)";

            // Format the series legend items.
            series1.LegendTextPattern = "{A}";

            // Adjust the position of series labels. 
            ((PieSeriesLabel)series1.Label).Position = PieSeriesLabelPosition.TwoColumns;

            // Detect overlapping of series labels.
            ((PieSeriesLabel)series1.Label).ResolveOverlappingMode = ResolveOverlappingMode.Default;

            // Access the view-type-specific options of the series.
            PieSeriesView myView = (PieSeriesView)series1.View;

            // Specify the pie rotation.
            myView.Rotation = -60;

            // Specify a data filter to explode points.
            myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Value_1,
                DataFilterCondition.GreaterThanOrEqual, 9));
            myView.ExplodedPointsFilters.Add(new SeriesPointFilter(SeriesPointKey.Argument,
                DataFilterCondition.NotEqual, "Others"));
            myView.ExplodeMode = PieExplodeMode.UseFilters;
            myView.ExplodedDistancePercentage = 30;
            myView.RuntimeExploding = true;

            // Customize the legend.
            pieChart.Legend.Visibility = DevExpress.Utils.DefaultBoolean.True;

            // Add the chart to the form.
            pieChart.Dock = DockStyle.Fill;
            this.Controls.Add(pieChart);
        }
    }
    public class DataPoint {
        public string Argument { get; set; }
        public double Value { get; set; }

        public static List<DataPoint> GetDataPoints() {
            return new List<DataPoint> {
                    new DataPoint { Argument = "Russia",    Value = 17.0752},
                    new DataPoint { Argument = "Canada",    Value = 9.98467},
                    new DataPoint { Argument = "USA",       Value = 9.63142},
                    new DataPoint { Argument = "China",     Value = 9.59696},
                    new DataPoint { Argument = "Brazil",    Value = 8.511965},
                    new DataPoint { Argument = "Australia", Value = 7.68685},
                    new DataPoint { Argument = "India",     Value = 3.28759},
                    new DataPoint { Argument = "Others",    Value = 81.2}
                };
        }
    }
}

Form1.vb

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

Namespace Series_PieChart
    Partial Public Class Form1
        Inherits DevExpress.XtraEditors.XtraForm

        Public Sub New()
            InitializeComponent()
        End Sub
        Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
            ' Create an empty chart.
            Dim pieChart As New ChartControl()

            pieChart.Titles.Add(New ChartTitle() With {.Text = "Land Area by Country"})

            ' Create a pie series.
            Dim series1 As New Series("Land Area by Country", ViewType.Pie)

            ' Bind the series to data.
            series1.DataSource = DataPoint.GetDataPoints()
            series1.ArgumentDataMember = "Argument"
            series1.ValueDataMembers.AddRange(New String() { "Value" })

            ' Add the series to the chart.
            pieChart.Series.Add(series1)

            ' Access diagram settings.
            Dim diagram As SimpleDiagram = CType(pieChart.Diagram, SimpleDiagram)
            diagram.Margins.All = 10

            ' Format the the series labels.
            series1.Label.TextPattern = "{VP:p0} ({V:.##}M km²)"

            ' Format the series legend items.
            series1.LegendTextPattern = "{A}"

            ' Adjust the position of series labels. 
            CType(series1.Label, PieSeriesLabel).Position = PieSeriesLabelPosition.TwoColumns

            ' Detect overlapping of series labels.
            CType(series1.Label, PieSeriesLabel).ResolveOverlappingMode = ResolveOverlappingMode.Default

            ' Access the view-type-specific options of the series.
            Dim myView As PieSeriesView = CType(series1.View, PieSeriesView)

            ' Specify a data filter to explode points.
            myView.ExplodedPointsFilters.Add(New SeriesPointFilter(SeriesPointKey.Value_1, DataFilterCondition.GreaterThanOrEqual, 9))
            myView.ExplodedPointsFilters.Add(New SeriesPointFilter(SeriesPointKey.Argument, DataFilterCondition.NotEqual, "Others"))
            myView.ExplodeMode = PieExplodeMode.UseFilters
            myView.ExplodedDistancePercentage = 30
            myView.RuntimeExploding = True

            ' Specify the pie rotation.
            myView.Rotation = -60

            ' Customize the legend.
            pieChart.Legend.Visibility = DevExpress.Utils.DefaultBoolean.True

            ' Add the chart to the form.
            pieChart.Dock = DockStyle.Fill
            Me.Controls.Add(pieChart)
        End Sub
    End Class
    Public Class DataPoint
        Public Property Argument() As String
        Public Property Value() As Double

        Public Shared Function GetDataPoints() As List(Of DataPoint)
            Return New List(Of DataPoint) From {
                New DataPoint With {
                    .Argument = "Russia",
                    .Value = 17.0752
                },
                New DataPoint With {
                    .Argument = "Canada",
                    .Value = 9.98467
                },
                New DataPoint With {
                    .Argument = "USA",
                    .Value = 9.63142
                },
                New DataPoint With {
                    .Argument = "China",
                    .Value = 9.59696
                },
                New DataPoint With {
                    .Argument = "Brazil",
                    .Value = 8.511965
                },
                New DataPoint With {
                    .Argument = "Australia",
                    .Value = 7.68685
                },
                New DataPoint With {
                    .Argument = "India",
                    .Value = 3.28759
                },
                New DataPoint With {
                    .Argument = "Others",
                    .Value = 81.2
                }
            }
        End Function
    End Class
End Namespace