BaseListBoxControl.SelectedIndexChanged Event

Allows you to respond to item selection.

Namespace: DevExpress.XtraEditors

Assembly: DevExpress.XtraEditors.v23.2.dll

NuGet Package: DevExpress.Win.Navigation

Declaration

C#

[DXCategory("Property Changed")]
public event EventHandler SelectedIndexChanged

VB.NET

<DXCategory("Property Changed")>
Public Event SelectedIndexChanged As EventHandler

Event Data

The SelectedIndexChanged event's data class is EventArgs.

Remarks

Handle the SelectedIndexChanged event to perform actions each time the selection has been changed. If the control functions in single selection mode, this event fires after the BaseListBoxControl.SelectedIndex property value has been changed. Usually this happens in the following cases:

• focus moves from one item to another;
• the item that was selected has been removed.

The list box control can, however, function in multi selection mode, allowing several items to be selected. In this case, the SelectedIndexChanged event fires each time the selection has been changed. The indexes of all items currently selected comprise the collection which can be accessed via control’s BaseListBoxControl.SelectedIndices property. The BaseListBoxControl.SelectedIndex property contains the first element in the collection in this case.

Example

In this example, a ListBoxControl displays a list of system colors. The following code handles the BaseListBoxControl.SelectedIndexChanged event to change the form’s background color when a user selects a color in the listbox:

C#

private void Form1_Load(object sender, EventArgs e) {
    Color[] colorArray = {
                   SystemColors.ActiveCaption,
                   SystemColors.ActiveCaptionText,
                   SystemColors.AppWorkspace,
                   SystemColors.Control,
                   SystemColors.ControlDark,
                   SystemColors.ControlLight,
                   SystemColors.ControlText,
                   SystemColors.Desktop,
                   SystemColors.Highlight,
                   SystemColors.InactiveBorder,
                   SystemColors.InactiveCaption,
                   SystemColors.Info,
                   SystemColors.InfoText,
                   SystemColors.Menu,
                   SystemColors.MenuText,
                   SystemColors.ScrollBar,
                   SystemColors.Window,
                   SystemColors.WindowFrame
                };
    listBoxControl1.DataSource = colorArray;
    listBoxControl1.DisplayMember = "Name";
    listBoxControl1.SelectedIndexChanged += ListBoxControl1_SelectedIndexChanged;
}

private void ListBoxControl1_SelectedIndexChanged(object sender, EventArgs e) {
    if (listBoxControl1.SelectedValue != null)
        this.BackColor = (Color)listBoxControl1.SelectedValue;
    else
        this.BackColor = Color.Black;
}

VB.NET

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    Dim colorArray() As Color = {
        SystemColors.ActiveCaption,
        SystemColors.ActiveCaptionText,
        SystemColors.AppWorkspace,
        SystemColors.Control,
        SystemColors.ControlDark,
        SystemColors.ControlLight,
        SystemColors.ControlText,
        SystemColors.Desktop,
        SystemColors.Highlight,
        SystemColors.InactiveBorder,
        SystemColors.InactiveCaption,
        SystemColors.Info,
        SystemColors.InfoText,
        SystemColors.Menu,
        SystemColors.MenuText,
        SystemColors.ScrollBar,
        SystemColors.Window,
        SystemColors.WindowFrame}
    ListBoxControl1.DataSource = colorArray
    ListBoxControl1.DisplayMember = "Name"
    AddHandler ListBoxControl1.SelectedIndexChanged, AddressOf ListBoxControl1_SelectedIndexChanged
End Sub

Private Sub ListBoxControl1_SelectedIndexChanged(sender As Object, e As EventArgs)
    If ListBoxControl1.SelectedValue IsNot Nothing Then
        Me.BackColor = CType(ListBoxControl1.SelectedValue, Color)
    Else
        Me.BackColor = Color.Black
    End If
End Sub

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the SelectedIndexChanged event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

winforms-create-custom-skinnable-font-edit/CS/CustomControlBinder.cs#L23

    DependControl.Properties.KeyDown += new System.Windows.Forms.KeyEventHandler(TextEdit_KeyDown);
    InitialControl.SelectedIndexChanged += new EventHandler(ListBoxControl_SelectedIndexChanged);
}

winforms-custom-imagecombobox-editor/CS/DXSample/MyPopupContainerEdit.cs#L116

base.OnPopupShown();
Properties.ListBox.SelectedIndexChanged += new EventHandler(ListBox_SelectedIndexChanged);
Properties.ListBox.MouseDown += new System.Windows.Forms.MouseEventHandler(ListBox_MouseDown);

VB.NET

winforms-create-custom-skinnable-font-edit/VB/CustomControlBinder.vb#L25

    AddHandler DependControl.Properties.KeyDown, AddressOf TextEdit_KeyDown
    AddHandler InitialControl.SelectedIndexChanged, AddressOf ListBoxControl_SelectedIndexChanged
End If

winforms-custom-imagecombobox-editor/VB/DXSample/MyPopupContainerEdit.vb#L126

MyBase.OnPopupShown()
AddHandler Properties.ListBox.SelectedIndexChanged, AddressOf ListBox_SelectedIndexChanged
AddHandler Properties.ListBox.MouseDown, AddressOf ListBox_MouseDown