DropDownList.SelectedIndex Property (System.Web.UI.WebControls)

SelectedIndex Property

.NET Framework Class Library

DropDownList..::.SelectedIndex Property

Gets or sets the index of the selected item in the DropDownList control.

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

Syntax

Visual Basic (Declaration)

Public Overrides Property SelectedIndex As Integer

Visual Basic (Usage)

Dim instance As DropDownList
Dim value As Integer

value = instance.SelectedIndex

instance.SelectedIndex = value

public override int SelectedIndex { get; set; }

Visual C++

public:
virtual property int SelectedIndex {
    int get () override;
    void set (int value) override;
}

JScript

public override function get SelectedIndex () : int
public override function set SelectedIndex (value : int)

ASP.NET

<asp:DropDownList SelectedIndex="Int32" />

Property Value

Type: System..::.Int32
The index of the selected item in the DropDownList control. The default value is 0, which selects the first item in the list.

Remarks

Use the SelectedIndex property to programmatically specify or determine the index of the selected item from the DropDownList control. An item is always selected in the DropDownList control. You cannot clear the selection from every item in the list at the same time.

Note:
The indexes for the items in the DropDownList control are zero-based.

Examples

The following code example demonstrates how to use the SelectedIndex property to determine the selected item in the DropDownList control.

Visual Basic

<%@ Page Language="VB" AutoEventWireup="True" %>

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

      Sub Selection_Change(sender As Object, e As EventArgs)

         ' Set the title format based on the value selected from the
         ' DropDownList control. The SelectedIndex property can be used
         ' to determine an enumeration value. Simply cast the value to 
         ' the appropriate enumeration type. Note that the value might
         ' need to be adjusted if the enumeration type is not zero-based.
         Calendar1.TitleFormat = CType(ModeList.SelectedIndex, TitleFormat)

      End Sub

   </script>

<head runat="server">
    <title> DropDownList SelectedIndex Example </title>
</head>
<body>

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

      <h3> DropDownList SelectedIndex Example </h3>

      Choose the title format.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Format:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ModeList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server">

                  <asp:ListItem> Month </asp:ListItem>
                  <asp:ListItem Selected="True"> MonthYear </asp:ListItem>

               </asp:DropDownList>

            </td>

         </tr>

      </table>   

   </form>

</body>
</html>

<%@ Page Language="C#" AutoEventWireup="True" %>

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

      void Selection_Change(Object sender, EventArgs e)
      {

         // Set the title format based on the value selected from the
         // DropDownList control. The SelectedIndex property can be used
         // to determine an enumeration value. Simply cast the value to 
         // the appropriate enumeration type. Note that the value might
         // need to be adjusted if the enumeration type is not zero-based. 
         Calendar1.TitleFormat = (TitleFormat)ModeList.SelectedIndex;

      }

   </script>

<head runat="server">
    <title> DropDownList SelectedIndex Example </title>
</head>
<body>

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

      <h3> DropDownList SelectedIndex Example </h3>

      Choose the title format.

      <br /><br /> 

      <asp:Calendar id="Calendar1"
           ShowGridLines="True" 
           ShowTitle="True"
           runat="server"/>

      <br /><br />

      <table cellpadding="5">

         <tr>

            <td>

               Format:

            </td>

         </tr>

         <tr>

            <td>

               <asp:DropDownList id="ModeList"
                    AutoPostBack="True"
                    OnSelectedIndexChanged="Selection_Change"
                    runat="server">

                  <asp:ListItem> Month </asp:ListItem>
                  <asp:ListItem Selected="True"> MonthYear </asp:ListItem>

               </asp:DropDownList>

            </td>

         </tr>

      </table>   

   </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

Reference

DropDownList Class

DropDownList Members

System.Web.UI.WebControls Namespace

Items