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Version Q2 2011 released 07/12/2011
select

ListBox / Validation

  • Apartments
  • Campings
  • Hotels
  • Hostels
  • Rooms
  • Villas
  • Burundi
  • Comoros
  • Djibouti
  • Eritrea
  • Ethiopia

  • This example demonstrates how to validate the selection of RadListBox. Each listbox is validated using RequiredFieldValidator control. If the user does not select an item the validators will fail and show their error message.

    Click the "Search Offers" button to trigger validation.

    ASPX

    <telerik:RadListBox runat="server" ID="RadListBox1">
	<Items>
		<telerik:RadListBoxItem Text="Apartments" />
		<telerik:RadListBoxItem Text="Campings" />
		<telerik:RadListBoxItem Text="Hotels" />
		<telerik:RadListBoxItem Text="Hostels" />
		<telerik:RadListBoxItem Text="Rooms" />
		<telerik:RadListBoxItem Text="Villas" />
	</Items>
</telerik:RadListBox>
<asp:RequiredFieldValidator runat="server" ID="RequiredFieldValidator1" 
ErrorMessage="Please, select item!" ControlToValidate="RadListBox1" />

Source Code

C# VB.NET
Show code in new window Demo isolation steps
  • <%@ Page Language="C#" AutoEventWireup="true" CodeFile="DefaultCS.aspx.cs" Inherits="ListBox_Examples_Functionality_Validation_DefaultCS" %>

    <%@ Register TagPrefix="qsf" Namespace="Telerik.QuickStart" %>
    <%@ Register TagPrefix="qsf" TagName="Header" Src="~/Common/Header.ascx" %>
    <%@ Register TagPrefix="qsf" TagName="HeadTag" Src="~/Common/HeadTag.ascx" %>
    <%@ Register TagPrefix="qsf" TagName="Footer" Src="~/Common/Footer.ascx" %>
    <%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>
    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <qsf:HeadTag runat="server" ID="Headtag1" />
        <link href="styles.css" rel="stylesheet" type="text/css" />
    </head>
    <body class="BODY">
        <form runat="server" id="mainForm" method="post">
        <telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
        <qsf:Header runat="server" ID="Header1" NavigationLanguage="C#" />
        <div class="example-panel">
            <label class="search-for">
                Search for:</label>
            <telerik:RadListBox runat="server" ID="RadListBox1" Width="180px" Height="140px" SelectionMode="Multiple">
                <Items>
                    <telerik:RadListBoxItem Text="Apartments" />
                    <telerik:RadListBoxItem Text="Campings" />
                    <telerik:RadListBoxItem Text="Hotels" />
                    <telerik:RadListBoxItem Text="Hostels" />
                    <telerik:RadListBoxItem Text="Rooms" />
                    <telerik:RadListBoxItem Text="Villas" />
                </Items>
            </telerik:RadListBox>
    <asp:RequiredFieldValidator runat="server" ID="RequiredFieldValidator1" ErrorMessage="Please, select item!"
    ControlToValidate="RadListBox1" />
            <label class="search-in">
                Search in:</label>
            <telerik:RadListBox runat="server" ID="RadListBox2" Width="180px" Height="140px" SelectionMode="Multiple">
                <Items>
                    <telerik:RadListBoxItem Text="Burundi" />
                    <telerik:RadListBoxItem Text="Comoros" />
                    <telerik:RadListBoxItem Text="Djibouti" />
                    <telerik:RadListBoxItem Text="Eritrea" />
                    <telerik:RadListBoxItem Text="Ethiopia" />
                </Items>
            </telerik:RadListBox>
    <asp:RequiredFieldValidator runat="server" ID="RequiredFieldValidator2" ErrorMessage="Please, select item!"
    ControlToValidate="RadListBox2" />
            <asp:ImageButton runat="server" ID="ImageButton1" ImageUrl="Images/button.png" />
            <asp:ValidationSummary runat="server" ID="ValidationSummary1" HeaderText="Invalid search" />
        </div>
        <qsf:Footer runat="server" ID="Footer1" />
        </form>
    </body>
    </html>

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