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    Add/Remove/Disable items

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    • Demo Configurator

    RadListBox provides rich server-side API. It allows the developer to easily add, remove or disable items.

    To add an item to the combo, simply create a new RadListBoxItem instance and add it to the Items collection of the combo:

    C#

    RadListBox1.Items.Add(new RadListBoxItem("Some Item"));

    VB.NET

    RadListBox1.Items.Add(New RadListBoxItem("Some Item"))

    To remove an item, simply call the Remove() method of the item.

    To disable an item, just set the Enabled property of the combo to false.

    • DefaultCS.aspx
    • DefaultCS.aspx.cs
    • ListBox.xml
    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="DefaultCS.aspx.cs" Inherits="ListBox.Examples.ServerSide.AddRemoveDisable.DefaultCS" %>
     
    <!DOCTYPE html>
    <html xmlns='http://www.w3.org/1999/xhtml'>
    <head runat="server">
        <title>Telerik ASP.NET Example</title>
    </head>
     
    <body>
        <form id="form1" runat="server">
        <telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
        <telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />
        <div class="demo-container size-thin">
            <telerik:RadListBox RenderMode="Lightweight" runat="server" ID="RadListBox1" SelectionMode="Multiple" Height="200"  Width="300">
            </telerik:RadListBox>
     
            <asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="Select a item first." Display="Dynamic" ControlToValidate="RadListBox1" ValidationGroup="DisableRequiresSelection" CssClass="validator" />
            <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ErrorMessage="Select a item first." Display="Dynamic" ControlToValidate="RadListBox1" ValidationGroup="DeleteRequiresSelection" CssClass="validator" />
        </div>
     
        <qsf:ConfiguratorPanel runat="server" ID="ConfigurationPanel1">
            <Views>
                <qsf:View>
                    <ul class="fb-group">
                        <li>
                            <qsf:Button ID="DisableButton" runat="server" OnClick="DisableButton_Click" ValidationGroup="DisableRequiresSelection" Text="Disable selected item(s)" />
                        </li>
                        <li>
                            <qsf:Button ID="EnableAllButton" runat="server" CausesValidation="False" OnClick="EnableAll_Button" Text="Enable all items" />
                        </li>
                        <li>
                            <qsf:Button ID="DeleteButton" runat="server" OnClick="DeleteButton_Click" ValidationGroup="DeleteRequiresSelection" Text="Delete selected item(s)" />
                        </li>
                        <li>
                            <qsf:TextBox runat="Server" ID="itemTextBox" EmptyMessage="Enter item text" Size="Wide" />
                            <qsf:Button ID="AddButton" runat="server" OnClick="AddButton_Click" ValidationGroup="TextRequired" Text="Add item" Size="Narrow" />
                            <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="Text is required" Display="Dynamic" ControlToValidate="itemTextBox" ValidationGroup="TextRequired" CssClass="validator" />
                        </li>
                        <li>
                        </li>
                    </ul>
                </qsf:View>
            </Views>
        </qsf:ConfiguratorPanel>
        </form>
    </body>
    </html>

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