.NET Framework Class Library
DropDownListSelectedIndex 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
Public Overrides Property SelectedIndex As [%$TOPIC/b3ffddfd_en-us_VS_110_2_0_0_0_0%]
public override [%$TOPIC/b3ffddfd_en-us_VS_110_2_0_1_0_0%] SelectedIndex { get; set; }
public:
virtual property [%$TOPIC/b3ffddfd_en-us_VS_110_2_0_2_0_0%] SelectedIndex {
	[%$TOPIC/b3ffddfd_en-us_VS_110_2_0_2_0_1%] get () override;
	void set ([%$TOPIC/b3ffddfd_en-us_VS_110_2_0_2_0_2%] value) override;
}
abstract SelectedIndex : [%$TOPIC/b3ffddfd_en-us_VS_110_2_0_3_0_0%] with get, set 
override SelectedIndex : [%$TOPIC/b3ffddfd_en-us_VS_110_2_0_3_0_1%] with get, set
<asp:[%$TOPIC/b3ffddfd_en-us_VS_110_2_0_4_0_0%] SelectedIndex="[%$TOPIC/b3ffddfd_en-us_VS_110_2_0_4_0_1%]" />

Property Value

Type: SystemInt32
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.

NoteNote

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.

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
Platforms

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.