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SelectedIndexChanged Event
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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

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>
    

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1
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