.NET Framework Class Library
ListControl..::.SelectedIndexChanged Event

Occurs when the selection from the list control changes between posts to the server.

Namespace:  System.Web.UI.WebControls
Assembly:  System.Web (in System.Web.dll)
Syntax

Visual Basic (Declaration)
Public Event SelectedIndexChanged As EventHandler
Visual Basic (Usage)
Dim instance As ListControl
Dim handler As EventHandler

AddHandler instance.SelectedIndexChanged, handler
C#
public event EventHandler SelectedIndexChanged
Visual C++
public:
 event EventHandler^ SelectedIndexChanged {
    void add (EventHandler^ value);
    void remove (EventHandler^ value);
}
JScript
JScript does not support events.
ASP.NET
<asp:ListControl OnSelectedIndexChanged="EventHandler" />
Remarks

The SelectedIndexChanged event is raised when the selection from the list control changes between posts to the server.

NoteNote:

A list control must persist some values between posts to the server for this event to work correctly. Be sure that view state is enabled for the list control.

For more information about handling events, see Consuming Events.

TopicLocation
How to: Respond to Changes in List Web Server ControlsBuilding ASP .NET Web Applications
How to: Respond to Changes in List Web Server ControlsBuilding ASP .NET Web Applications
How to: Respond to Changes in List Web Server ControlsBuilding ASP .NET Web Applications in Visual Studio
How to: Respond to Changes in List Web Server ControlsBuilding ASP .NET Web Applications in Visual Studio
Examples

The following example demonstrates how to specify and code a handler for the SelectedIndexChanged event to display the selection made by the user.

Visual Basic
<%@ Page Language="VB" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
 <script language="vb" runat="server">

    Function CreateDataSource() As ICollection
        Dim dt As New DataTable()
        Dim dr As DataRow

        dt.Columns.Add(New DataColumn("IntegerValue", GetType(Int32)))
        dt.Columns.Add(New DataColumn("StringValue", GetType(String)))
        dt.Columns.Add(New DataColumn("DateTimeValue", GetType(DateTime)))
        dt.Columns.Add(New DataColumn("BoolValue", GetType(Boolean)))
        dt.Columns.Add(New DataColumn("CurrencyValue", GetType(Double)))

        Dim i As Integer
        For i = 0 To 8
            dr = dt.NewRow()

            dr(0) = i
            dr(1) = "Item " + i.ToString()
            dr(2) = DateTime.Now
            If (i Mod 2) <> 0 Then
                dr(3) = True
            Else
                dr(3) = False
            End If
            dr(4) = 1.23 *(i + 1)

            dt.Rows.Add(dr)
        Next i

        Dim dv As New DataView(dt)
        Return dv
    End Function

    Sub Page_Load(sender As Object, e As EventArgs)
        If Not IsPostBack Then
            RadioButtonList1.DataSource = CreateDataSource()
            RadioButtonList1.DataTextField = "StringValue"
            RadioButtonList1.DataValueField = "CurrencyValue"
            RadioButtonList1.DataBind()
        End If
    End Sub

    Sub Index_Changed(sender As Object, e As EventArgs)        
        Label1.Text = "You selected " & RadioButtonList1.SelectedItem.Text & _
            " with a value of : " & RadioButtonList1.SelectedItem.Value & "."
    End Sub

 </script>

 <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>

    <form id="form1" runat="server">

       <asp:RadioButtonList id="RadioButtonList1" 
            OnSelectedIndexChanged="Index_Changed"
            AutoPostBack="true"
            runat="server"/>

       <br />

       <asp:Label id="Label1" runat="server"/>

    </form>

 </body>
 </html>

C#
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
 <script language="c#" runat="server">

    ICollection CreateDataSource() {
       DataTable dt = new DataTable();
       DataRow dr;

       dt.Columns.Add(new DataColumn("IntegerValue", typeof(Int32)));
       dt.Columns.Add(new DataColumn("StringValue", typeof(string)));
       dt.Columns.Add(new DataColumn("DateTimeValue", typeof(DateTime)));
       dt.Columns.Add(new DataColumn("BoolValue", typeof(bool)));
       dt.Columns.Add(new DataColumn("CurrencyValue", typeof(double)));

       for (int i = 0; i < 9; i++) {
          dr = dt.NewRow();

          dr[0] = i;
          dr[1] = "Item " + i.ToString();
          dr[2] = DateTime.Now;
          dr[3] = (i % 2 != 0) ? true : false;
          dr[4] = 1.23 * (i+1);

          dt.Rows.Add(dr);
       }

       DataView dv = new DataView(dt);
       return dv;
    }

    void Page_Load(Object sender, EventArgs e) {
       if (!IsPostBack) {
          RadioButtonList1.DataSource = CreateDataSource();
          RadioButtonList1.DataTextField="StringValue";
          RadioButtonList1.DataValueField="CurrencyValue";
          RadioButtonList1.DataBind();
       }
    }

    void Index_Changed(Object sender, EventArgs e) {

       Label1.Text = "You selected " + RadioButtonList1.SelectedItem.Text +
                     " with a value of $" + RadioButtonList1.SelectedItem.Value +
                     ".";

    }

 </script>

 <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>

    <form id="form1" runat="server">

       <asp:RadioButtonList id="RadioButtonList1" 
            OnSelectedIndexChanged="Index_Changed"
            AutoPostBack="true"
            runat="server"/>

       <br />

       <asp:Label id="Label1" runat="server"/>

    </form>

 </body>
 </html>

JScript
<%@ Page Language="JScript" AutoEventWireup="True" %>
<%@ Import Namespace="System.Data" %>

 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html  >
 <script language="jscript" runat="server">

    function CreateDataSource() : ICollection{
        var dt : DataTable = new DataTable()
        var dr : DataRow

        dt.Columns.Add(new DataColumn("IntegerValue", System.Int32))
        dt.Columns.Add(new DataColumn("StringValue", System.String))
        dt.Columns.Add(new DataColumn("DateTimeValue", System.DateTime))
        dt.Columns.Add(new DataColumn("BoolValue", System.Boolean))
        dt.Columns.Add(new DataColumn("CurrencyValue", System.Double))

        var i : int
        for( i = 0; i < 9; i++){
            dr = dt.NewRow()

            dr("IntegerValue") = i
            dr("StringValue") = "Item " + i.ToString()
            dr("DateTimeValue") = DateTime.Now
            dr("BoolValue") = ((i % 2) != 0) ? true : false
            dr("CurrencyValue") = 1.23 *(i + 1)

            dt.Rows.Add(dr)
        }

        var dv : DataView = new DataView(dt)
        return dv
    }

    function Page_Load(sender : Object, e : EventArgs){
        if(!IsPostBack){
            RadioButtonList1.DataSource = CreateDataSource()
            RadioButtonList1.DataTextField = "StringValue"
            RadioButtonList1.DataValueField = "CurrencyValue"
            RadioButtonList1.DataBind()
        }
    }

    function Index_Changed(sender : Object, e : EventArgs){
        Label1.Text = "You selected " + RadioButtonList1.SelectedItem.Text
                    + " with a value of : " + RadioButtonList1.SelectedItem.Value + "."
    }

 </script>

 <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>

    <form id="form1" runat="server">

       <asp:RadioButtonList id="RadioButtonList1" 
            OnSelectedIndexChanged="Index_Changed"
            AutoPostBack="true"
            runat="server"/>

       <br />

       <asp:Label id="Label1" runat="server"/>

    </form>

 </body>
 </html>

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Version Information

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
See Also

Reference

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