ChartControl.SelectedItemsChanged Event

Occurs after the selection of a chart item has been changed.

Namespace: DevExpress.XtraCharts

Assembly: DevExpress.XtraCharts.v20.1.UI.dll

Declaration

public event SelectedItemsChangedEventHandler SelectedItemsChanged
Public Event SelectedItemsChanged As SelectedItemsChangedEventHandler

Event Data

The SelectedItemsChanged event's data class is SelectedItemsChangedEventArgs. The following properties provide information specific to this event:

Property Description
Action Gets an action which describes how the collection has been changed.
NewItems Provides access to a collection of new selected chart elements (series and series points) and business data objects if a Chart Control or a series is bound to a data source.
OldItems Provides access to previously selected chart elements (series and series points) and business data objects if a Chart Control or a series is bound to a data source.

Remarks

Use the SelectedItemsChanged event to customize the chart control behavior when the chart items and/ or business data objects (when using data binding) are selected.

For instance, you can display only bar series which correspond to the selected pie segments, as shown below.

SelectedItems

Examples

This example shows how to obtain currently selected series points and show them in another chart. To do this, the ChartControl.SelectedItemsChanged event should be used.

In this example, you can choose the selection behavior (Single, Multiple or Extended) from the Selection Mode combo box. When any country is selected in the pie chart, you can see the population dynamics for each country in the bar chart. To cancel pie segment selection, choose None in the Selection Mode combo box.

In addition, this example demonstrates how to colorize each bar series point in the pie specific color using the ChartControl.CustomDrawSeriesPoint event.

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

namespace ChartSelection {

    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        PaletteEntry[] paletteEntries;

        private void Form1_Load(object sender, EventArgs e) {

            // Specify selection mode for the Pie chart.
            this.cbSelectionMode.Properties.Items.AddRange(Enum.GetValues(typeof(ElementSelectionMode)));
            this.cbSelectionMode.SelectedIndex = 2;
            pieChart.SeriesSelectionMode = SeriesSelectionMode.Point;

            // Handle the SelectedItemsChanged event for the Pie chart.                
            pieChart.SelectedItemsChanged += pieChart_SelectedItemsChanged;

            // Handle the CustomDrawSeriesPoint event for the Bar chart. 
            barChart.CustomDrawSeriesPoint += barChart_CustomDrawSeriesPoint;

            // Get palette entries of the pie chart.
            paletteEntries = pieChart.GetPaletteEntries(pieChart.Series[0].Points.Count);
        }

        private void cbSelectionMode_SelectedIndexChanged(object sender, EventArgs e) {
            pieChart.SelectionMode = (ElementSelectionMode)this.cbSelectionMode.SelectedItem;
        }

        private void pieChart_SelectedItemsChanged(object sender, SelectedItemsChangedEventArgs e) {
            barChart.Series[0].Points.Clear();

            foreach (SeriesPoint piePoint in pieChart.SelectedItems) {
                SeriesPoint barPoint = new SeriesPoint(piePoint.Argument, piePoint.Values[0]);
                barPoint.Tag = pieChart.Series[0].Points.IndexOf(piePoint);
                barChart.Series[0].Points.Add(barPoint);
            }
        }

        private void barChart_CustomDrawSeriesPoint(object sender, CustomDrawSeriesPointEventArgs e) {
            BarDrawOptions barOptions = e.SeriesDrawOptions as BarDrawOptions;
            int colorIndex = (int)e.SeriesPoint.Tag;
            barOptions.Color = paletteEntries[colorIndex].Color;
        }
    }
}

Implements

DevExpress.XtraCharts.Native.IChartInteractionProvider.SelectedItemsChanged
See Also