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HtmlSelect.SelectedIndex Property

Gets or sets the ordinal index of the selected item in an HtmlSelect control.

[Visual Basic]
Public Overridable Property SelectedIndex As Integer
[C#]
public virtual int SelectedIndex {get; set;}
[C++]
public: __property virtual int get_SelectedIndex();
public: __property virtual void set_SelectedIndex(int);
[JScript]
public function get SelectedIndex() : int;
public function set SelectedIndex(int);

Property Value

The ordinal index of the selected item in an HtmlSelect control. A value of -1 indicates that no item is selected.

Remarks

The SelectedIndex property is commonly used to determine the index of the selected item in a single-selection HtmlSelect control. This index can then be used to retrieve the item from the Items collection.

If multiple selection is enabled, by setting the Multiple property to true, this property contains the index of the first selected item. To determine the selected items from an HtmlSelect control that allows multiple simultaneous selections, iterate through the Items collection and test the ListItem.Selected property of each item.

CAUTION   It is possible to have no item selected. If no item is selected, the SelectedIndex property contains a value of -1. This commonly occurs when the page first loads and an item is not selected by default. Provide code to test this value before referencing the item in the Items collection. Otherwise, an exception is thrown if the index is out of the range of the collection.

By default, the HtmlSelect control is displayed as a drop-down list box. If you allow multiple selections (by setting the Multiple property to true) or specify a height greater than one row (by setting the Size property to a value greater than 1), the control is displayed as a list box. If a drop-down list box is displayed, an item is always selected. If a list box is displayed, you can programmatically deselect all items by setting the SelectedIndex property to -1.

Example

[Visual Basic, C#, JScript] The following example demonstrates how to use the SelectedIndex property to determine the index of the selected item in the HtmlSelect control. The index is then used to retrieve the selected item from the Items collection.

[Visual Basic] 

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

<html>

<head>

   <script runat="server">

      Sub Button_Click (sender As Object, e As EventArgs)
        
         Label1.Text = "You selected the item with index number " & _
                       Select1.SelectedIndex.ToString() & _
                       " and contains the value " & _
                       Select1.Value & "."

      End Sub

   </script>

</head>

<body>

   <form runat="server">

      <h3> HtmlSelect Example </h3>

      Select items from the list: <br><br>

      <select id="Select1" 
              Multiple="False"
              runat="server">

         <option value="Text for Item 1" Selected="True"> Item 1 </option>
         <option value="Text for Item 2"> Item 2 </option>
         <option value="Text for Item 3"> Item 3 </option>
         <option value="Text for Item 4"> Item 4 </option>
         <option value="Text for Item 5"> Item 5 </option>
         <option value="Text for Item 6"> Item 6 </option>

      </select>

      <br><br>

      <button id="Button1"
              OnServerClick="Button_Click"
              runat="server">

         Submit

      </button>

      <br><br>

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

   </form>

</body>

</html>


[C#] 

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

<html>

<head>

   <script runat="server">

      void Button_Click (Object sender, EventArgs e)
      {
        
         Label1.Text = "You selected the item with index number " + 
                       Select1.SelectedIndex.ToString() + 
                       " and contains the value " +
                       Select1.Value + ".";

      }

   </script>

</head>

<body>

   <form runat="server">

      <h3> HtmlSelect Example </h3>

      Select items from the list: <br><br>

      <select id="Select1" 
              Multiple="False"
              runat="server">

         <option value="Text for Item 1" Selected="True"> Item 1 </option>
         <option value="Text for Item 2"> Item 2 </option>
         <option value="Text for Item 3"> Item 3 </option>
         <option value="Text for Item 4"> Item 4 </option>
         <option value="Text for Item 5"> Item 5 </option>
         <option value="Text for Item 6"> Item 6 </option>

      </select>

      <br><br>

      <button id="Button1"
              OnServerClick="Button_Click"
              runat="server">

         Submit

      </button>

      <br><br>

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

   </form>

</body>

</html>


[JScript] 

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

<html>

<head>

   <script runat="server">

      function Button_Click (sender : Object, e: EventArgs) :  void
      {
        
         Label1.Text = "You selected the item with index number " + 
                       Select1.SelectedIndex.ToString() + 
                       " and contains the value " +
                       Select1.Value + ".";

      }

   </script>

</head>

<body>

   <form runat="server">

      <h3> HtmlSelect Example </h3>

      Select items from the list: <br><br>

      <select id="Select1" 
              Multiple="False"
              runat="server">

         <option value="Text for Item 1" Selected="True"> Item 1 </option>
         <option value="Text for Item 2"> Item 2 </option>
         <option value="Text for Item 3"> Item 3 </option>
         <option value="Text for Item 4"> Item 4 </option>
         <option value="Text for Item 5"> Item 5 </option>
         <option value="Text for Item 6"> Item 6 </option>

      </select>

      <br><br>

      <button id="Button1"
              OnServerClick="Button_Click"
              runat="server">

         Submit

      </button>

      <br><br>

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

   </form>

</body>

</html>

[C++] No example is available for C++. To view a Visual Basic, C#, or JScript example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

HtmlSelect Class | HtmlSelect Members | System.Web.UI.HtmlControls Namespace | Items | ListItem.Selected | Multiple | Size

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