AutoCompleteExtender sample

using System;
using System.Web;
using System.Collections;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Web.Script.Services;
using System.Collections.Generic;
using DomainObjects;


/**//// <summary>
/// Summary description for GetUserNames
/// </summary>
[WebService(Namespace = "http://www.urbanlighthouse.com/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class GetUserNames : System.Web.Services.WebService
{
    [WebMethod]
    public string[] GetCompletionList(string prefixText, int count)
    {
        return (new UserDO()).retrieveUserNames(prefixText, count);
    }
}

<%@ Page Language="C#" MasterPageFile="~/Admin/FCC_VisionAdmin.master" AutoEventWireup="true"
    CodeFile="BankAdministration.aspx.cs" Inherits="Admin_BankAdministration" Title="Bank Administration" %>

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="AjaxControlToolkit" %>
<%@ Register TagPrefix="UC" TagName="NotificationLabel" Src="..\Controls\NotificationLabel.ascx" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">
    <div>
        <UC:NotificationLabel ID="nlMessage" DirtyCSS="CommonErrorMessage CommonDirtyMessage"
            CleanCSS="CommonErrorMessage CommonCleanMessage" runat="server" />
    </div>
    <div runat="Server" id="RadioButtonZone">
        <div style="float: left; width: 210px;">
            <asp:Label runat="server" ID="lblRadioButton" meta:resourcekey="lblRadioButton"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:RadioButton Checked="true" runat="server" ID="rbAdjust" GroupName="Choice" OnCheckedChanged="rbAdjust_CheckedChanged"
                meta:resourcekey="rbAdjust" AutoPostBack="True" />
            <asp:RadioButton runat="server" ID="rbTransfer" GroupName="Choice" OnCheckedChanged="rbTransfer_CheckedChanged"
                meta:resourcekey="rbTransfer" AutoPostBack="True" />
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
    </div>
    <div runat="server" id="AdjustingZone">
        <div style="float: left; width: 200px;">
            <asp:Label runat="server" ID="lblAdjustUserName" meta:resourcekey="lblUserName"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:TextBox runat="server" ID="txtAdjustUserName"></asp:TextBox>
            <AjaxControlToolkit:AutoCompleteExtender runat="server" ID="aceAdjustUserName" TargetControlID="txtAdjustUserName"
                ServiceMethod="GetCompletionList" ServicePath="../GetUserNames.asmx" MinimumPrefixLength="3"
                EnableCaching="true">
            </AjaxControlToolkit:AutoCompleteExtender>
            <asp:RequiredFieldValidator runat="server" ID="rfvAdjustUserName" ControlToValidate="txtAdjustUserName"
                Display="Dynamic" Text="*" ValidationGroup="vgAdjust" meta:resourcekey="rfvAdjustUserName">
            </asp:RequiredFieldValidator>
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
        <div style="float: left; width: 200px;">
            <asp:Label runat="server" ID="lblAdjustPoints" meta:resourcekey="lblPoints"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:TextBox runat="server" ID="txtAdjustPoints"></asp:TextBox>
            <asp:RequiredFieldValidator runat="server" ID="rfvAdjustPoints" ControlToValidate="txtAdjustPoints"
                Display="Dynamic" Text="*" ValidationGroup="vgAdjust" meta:resourcekey="rfvPoints">
            </asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator runat="server" ID="revAdjustPoints" ControlToValidate="txtAdjustPoints"
                Display="Dynamic" ValidationExpression="^[-+]?\d+$" Text="*" ValidationGroup="vgAdjust"
                meta:resourcekey="revPoints">
            </asp:RegularExpressionValidator>
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
        <div>
            <asp:Button meta:resourcekey="btnAdjust" runat="server" ID="btnAdjust" ValidationGroup="vgAdjust"
                CausesValidation="true" OnClick="btnAdjust_Click" />
        </div>
        <div>
            <asp:ValidationSummary runat="server" ID="vsAdjust" ValidationGroup="vgAdjust" DisplayMode="List" />
        </div>
    </div>
    <div runat="server" id="TransferringZone" visible="false">
        <div style="float: left; width: 200px;">
            <asp:Label runat="server" ID="lblTransferFromUserName" meta:resourcekey="lblFromUserName"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:TextBox runat="server" ID="txtTransferFromUserName"></asp:TextBox>
            <AjaxControlToolkit:AutoCompleteExtender runat="server" ID="aceTransferFromUserName"
                TargetControlID="txtTransferFromUserName" ServiceMethod="GetCompletionList" ServicePath="../GetUserNames.asmx"
                MinimumPrefixLength="3" EnableCaching="true">
            </AjaxControlToolkit:AutoCompleteExtender>
            <asp:RequiredFieldValidator runat="server" ID="rfvTransferFromUserName" ControlToValidate="txtTransferFromUserName"
                Display="Dynamic" Text="*" ValidationGroup="vgTransfer" meta:resourcekey="rfvTransferFromUserName">
            </asp:RequiredFieldValidator>
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
        <div style="float: left; width: 200px;">
            <asp:Label runat="server" ID="lblTransferToUserName" meta:resourcekey="lblToUserName"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:TextBox runat="server" ID="txtTransferToUserName"></asp:TextBox>
            <AjaxControlToolkit:AutoCompleteExtender runat="server" ID="aceTransferToUserName"
                TargetControlID="txtTransferToUserName" ServiceMethod="GetCompletionList" ServicePath="../GetUserNames.asmx"
                MinimumPrefixLength="3" EnableCaching="true">
            </AjaxControlToolkit:AutoCompleteExtender>
            <asp:RequiredFieldValidator runat="server" ID="rfvTransferToUserName" ControlToValidate="txtTransferToUserName"
                Display="Dynamic" Text="*" ValidationGroup="vgTransfer" meta:resourcekey="rfvTransferToUserName">
            </asp:RequiredFieldValidator>
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
        <div style="float: left; width: 200px;">
            <asp:Label runat="server" ID="lblTransferPoints" meta:resourcekey="lblTransferPoints"></asp:Label>
        </div>
        <div style="float: left;">
            <asp:TextBox runat="server" ID="txtTransferPoints"></asp:TextBox>
            <asp:RequiredFieldValidator runat="server" ID="rfvTransferPoints" ControlToValidate="txtTransferPoints"
                Display="Dynamic" Text="*" ValidationGroup="vgTransfer" meta:resourcekey="rfvPoints">
            </asp:RequiredFieldValidator>
            <asp:RegularExpressionValidator runat="server" ID="revTransferPoints" ControlToValidate="txtTransferPoints"
                Display="Dynamic" ValidationExpression="\d+$" Text="*" ValidationGroup="vgTransfer"
                meta:resourcekey="revPoints">
            </asp:RegularExpressionValidator>
        </div>
        <div style="clear: both; float: none; font-size: 0.1%;">
        </div>
        <div>
            <asp:Button meta:resourcekey="btnTransfer" runat="server" ID="btnTransfer" ValidationGroup="vgTransfer"
                CausesValidation="true" OnClick="btnTransfer_Click" />
        </div>
        <div>
            <asp:ValidationSummary runat="server" ID="vsTransfer" ValidationGroup="vgTransfer"
                DisplayMode="List" />
        </div>
    </div>
    <asp:ScriptManager EnablePageMethods="true" ID="sm" runat="server">
        <services>
            <asp:ServiceReference Path="GetUserNames.asmx" />
        </services>
    </asp:ScriptManager>
</asp:Content>