ListItem.Enabled Property
Assembly: System.Web (in system.web.dll)
The Enabled property allows you to specify whether a ListItem control is enabled or disabled. A ListItem control that is disabled is dimmed to indicate that it cannot be selected. Use this property to disable a ListItem control in either a RadioButtonList control or a CheckBoxList control.
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| You cannot use this property to disable a ListItem control in a DropDownList control or ListBox control. |
The following example demonstrates how to use the Enabled property to programmatically disable list items in a RadioButtonList control. The first question asks the user to select the radio button that corresponds to the user's occupation. If the user indicates that he or she is not a developer, the list items in the second radio button list are disabled. The second question asks the user to select a primary programming language. This question is not relevant to a user that is not a developer.
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| The following code sample uses the single-file code model and may not work correctly if copied directly into a code-behind file. This code sample must be copied into an empty text file that has an .aspx extension. For more information on the Web Forms code model, see ASP.NET Web Page Code Model. |
<%@ Page Language="VB" %> <html> <head> <script runat="server"> Sub Index_Changed(ByVal sender As Object, ByVal e As System.EventArgs) Dim i As Integer ' If the user is not a developer, do not ' ask the user to select a programming language. If radiobuttonlist1.SelectedIndex = 2 Then ' Clear any previously selected list ' items in the second question. Radiobuttonlist2.SelectedIndex = -1 ' Disable all the list items in the second question. For i = 0 To Radiobuttonlist2.Items.Count - 1 Radiobuttonlist2.Items(i).Enabled = False Next Else ' Enable all the list items in the second question. For i = 0 To Radiobuttonlist2.Items.Count - 1 Radiobuttonlist2.Items(i).Enabled = True Next i End If End Sub </script> </head> <body> <form id="Form1" runat="server"> <h3>ListItem.Enabled Property Example</h3> Select your occupation: <asp:radiobuttonlist id="RadioButtonList1" autopostback=true onselectedindexchanged="Index_Changed" runat="server"> <asp:ListItem>Web developer</asp:ListItem> <asp:ListItem>Windows developer</asp:ListItem> <asp:ListItem>Occupation other than developer</asp:ListItem> </asp:radiobuttonlist> <br /><br /> Select your primary programming language: <asp:radiobuttonlist id="RadioButtonList2" runat="server"> <asp:ListItem>Visual Basic .NET</asp:ListItem> <asp:ListItem>C#</asp:ListItem> <asp:ListItem>C++</asp:ListItem> <asp:ListItem>Other</asp:ListItem> </asp:radiobuttonlist> </form> </body> </html>
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Reference
ListItem ClassListItem Members
System.Web.UI.WebControls Namespace
RadioButtonList
CheckBoxList Class
ListControl Class
RadioButtonList
ListBox Class
DropDownList Class
CheckBoxList Class
Other Resources
ListBox Web Server ControlRadioButton and RadioButtonList Web Server Controls Overview
CheckBox and CheckBoxList Web Server Controls
BulletedList Web Server Control
DropDownList Web Server Control
Note