WebChartControl.SelectedItemsChanged Event

Occurs after chart items are selected.

Namespace: DevExpress.XtraCharts.Web

Assembly: DevExpress.XtraCharts.v24.1.Web.dll

NuGet Package: DevExpress.Web.Visualization

Declaration

C#

public event SelectedItemsChangedEventHandler SelectedItemsChanged

VB.NET

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 WebChartControl when the chart items including business data objects (if the control is connected to a data source) are selected.

For instance, you can display only bar series which correspond to the selected pie segments:

ASPX

 <dx:WebChartControl ID="WebChartControlPie" EnableCallBacks="False" runat="server" Height="250px" Width="700px" CrosshairEnabled="False" RenderFormat="Svg"
                ClientInstanceName="chartTotal" OnObjectSelected="WebChartControlPie_ObjectSelected" DataSourceID="chartDataSource1"
                SelectionMode="Multiple" SeriesSelectionMode="Point" OnSelectedItemsChanged="WebChartControlPie_SelectedItemsChanged">

 </dx:WebChartControl>

C#

protected void WebChartControlPie_SelectedItemsChanged(object sender, SelectedItemsChangedEventArgs e) {
    InitColorIndices();
    paletteIndices = new List<int>();
    IList selectedItems = WebChartControlPie.SelectedItems;
    if (selectedItems == null || selectedItems.Count == 0)
        WebChartControlBars.SeriesTemplate.FilterCriteria = null;
    else {
        List<CriteriaOperator> filters = new List<CriteriaOperator>();
        HashSet<string> regions = new HashSet<string>();
        foreach (DevAVDataItem dataItem in WebChartControlPie.SelectedItems) {
            string region = dataItem.Region;
            if (!regions.Contains(region)) {
                filters.Add(new BinaryOperator(RegionDataMember, region, BinaryOperatorType.Equal));
                paletteIndices.Add(colorIndices[region]);
                regions.Add(region);
            }
        }
        WebChartControlBars.SeriesTemplate.FilterCriteria = new GroupOperator(filters.ToArray()) { OperatorType = GroupOperatorType.Or };
    }
}

VB.NET

Protected Sub WebChartControlPie_SelectedItemsChanged(ByVal sender As Object, ByVal e As SelectedItemsChangedEventArgs)
    InitColorIndices()
    paletteIndices = New List(Of Integer)()
    Dim selectedItems As IList = WebChartControlPie.SelectedItems
    If selectedItems Is Nothing OrElse selectedItems.Count = 0 Then
        WebChartControlBars.SeriesTemplate.FilterCriteria = Nothing
    Else
        Dim filters As New List(Of CriteriaOperator)()
        Dim regions As New HashSet(Of String)()
        For Each dataItem As DevAVDataItem In WebChartControlPie.SelectedItems
            Dim region As String = dataItem.Region
            If Not regions.Contains(region) Then
                filters.Add(New BinaryOperator(RegionDataMember, region, BinaryOperatorType.Equal))
                paletteIndices.Add(colorIndices(region))
                regions.Add(region)
            End If
        Next dataItem
        WebChartControlBars.SeriesTemplate.FilterCriteria = New GroupOperator(filters.ToArray()) With {.OperatorType = GroupOperatorType.Or}
    End If
End Sub