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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)

public event EventHandler SelectedIndexChanged
<asp:ListControl OnSelectedIndexChanged="EventHandler" />

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

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

<%@ 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 xmlns="http://www.w3.org/1999/xhtml" >
 <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>

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.

.NET Framework

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

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