ChartBase.SelectionChanged Event

Occurs when the chart selection is changed.

Namespace: DevExpress.WinUI.Charts

Assembly: DevExpress.WinUI.Charts.v21.1.dll

Declaration

C#

public event ChartElementSelectionChangedEventHandler SelectionChanged

VB.NET

Public Event SelectionChanged As ChartElementSelectionChangedEventHandler

Event Data

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

Property	Description
ChangedElement	Returns the chart element that is currently selected or deselected.
IsSelected	Returns the selection state of the chart element that is currently selected or deselected.
Selection	Returns the list of currently selected objects. Inherited from ElementSelectionChangedEventArgs.

Remarks

The ChartBase.SelectionChanged event occurs when a user selects or deselects series points. Use the e.Selection property to obtain selected items. The following example calculates total area of the selected countries:

C#

private void chartOfCountriesArea_SelectionChanged(object sender, ChartElementSelectionChangedEventArgs e) {
    double totalArea = 0;
    foreach (CountryStatisticInfo point in e.Selection) {
        totalArea += point.AreaMSqrKilometers;
    }
    selectedItemsText.Text = String.Format("Total area of ​​selected countries: {0}", totalArea);
}

VB.NET

Private Sub chartOfCountriesArea_SelectionChanged(ByVal sender As Object, ByVal e As ChartElementSelectionChangedEventArgs)
    Dim totalArea As Double = 0
    For Each point As CountryStatisticInfo In e.Selection
        totalArea += point.AreaMSqrKilometers
    Next
    selectedItemsText.Text = String.Format("Total area of ​​selected countries: {0}", totalArea)
End Sub

Use the e.ChangedElement property to get the series point whose selection state is changed. The e.IsSelected property returns this selection state. The following code calls a custom UpdateStatistics method for the last selected series point:

C#

private void chartOfCountriesArea_SelectionChanged(object sender, ChartElementSelectionChangedEventArgs e) {
    selectedItemsText.Text = String.Format("Total area of ​​selected countries: {0}", totalArea);
    if (e.IsSelected) {
        UpdateStatistics((CountryStatisticInfo)e.ChangedElement);
    }
}

VB.NET

Private Sub chartOfCountriesArea_SelectionChanged(ByVal sender As Object, ByVal e As ChartElementSelectionChangedEventArgs)
    selectedItemsText.Text = String.Format("Total area of ​​selected countries: {0}", totalArea)
    If e.IsSelected Then
        UpdateStatistics(CType(e.ChangedElement, CountryStatisticInfo))
    End If
End Sub