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ListControl.AutoPostBack Property

Gets or sets a value indicating whether a postback to the server automatically occurs when the user changes the list selection.

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

[ThemeableAttribute(false)]
public virtual bool AutoPostBack { get; set; }
<asp:ListControl AutoPostBack="True|False" />

Property Value

Type: System.Boolean
true if a postback to the server automatically occurs whenever the user changes the selection of the list; otherwise, false. The default is false.

Set this property to true if the server needs to capture the selection as soon as it is made. For example, other controls on the Web page can be automatically filled depending on the user's selection from a list control.

This property can be used to allow automatic population of other controls on the Web page based on a user's selection from a list.

The value of this property is stored in view state.

This property cannot be set by themes or style sheet themes. For more information, see ThemeableAttribute and ASP.NET Themes and Skins Overview.

The following example demonstrates how to enable AutoPostBack for the ListBox control.

<%@ 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" >
<head runat="server">
    <title>ListBox AutoPostBack Example</title>
<script runat="server">

      void Page_Load(Object sender, EventArgs e)
      {
         if (ListBox1.SelectedItem != null)
            Label1.Text = "You selected: " + ListBox1.SelectedItem.Value;
         else
            Label1.Text = "";
      }

   </script>

</head>

<body>

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

      <h3>ListBox AutoPostBack Example</h3>

      Select an item from the list box: <br /><br />

      <asp:ListBox id="ListBox1" 
           Rows="4"
           AutoPostBack="True" 
           SelectionMode="Single"  
           runat="server">

         <asp:ListItem>Item 1</asp:ListItem>
         <asp:ListItem>Item 2</asp:ListItem>
         <asp:ListItem>Item 3</asp:ListItem>
         <asp:ListItem>Item 4</asp:ListItem>
         <asp:ListItem>Item 5</asp:ListItem>
         <asp:ListItem>Item 6</asp:ListItem>

      </asp:ListBox>

      <br /><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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