How to implement jQuery AutoComplete inside GridView in ASP.Net

Hi,

I am using j-query auto complete plugin in textbox that is inside gridview.  The autocomplete only works when my gridview has more than 1 row, if my gridview has only one row then the autocomplete will not work.  I have spent days and days for this, so please please help.  I am using the same code i downloaed from this website.  Here is my code for the gridview:

<asp:GridView ID="GV_Test" runat="server" Width="870px"
                    AutoGenerateColumns="False" Font-Names="Arial" Font-Size="11pt" AlternatingRowStyle-BackColor="#C2D69B"
                    HeaderStyle-BackColor="green" ShowFooter="True" 
                      
                    CellPadding="4" BackColor="White" BorderColor="#336666" 
                    BorderStyle="Double" BorderWidth="3px"
                    DataKeyNames="ID">
                    <AlternatingRowStyle BackColor="#C2D69B" />
                    <Columns>
                       
                       <asp:TemplateField ItemStyle-Width="30px" HeaderText="ID" Visible = "True">
                            <ItemTemplate>
                                <asp:Label ID="lblTSK_ID" runat="server" Text='<%# Eval("ID")%>'></asp:Label>
                            </ItemTemplate>                       
                            <ItemStyle Width="10px" />
                        </asp:TemplateField>


                       <asp:TemplateField ItemStyle-Width="150px" HeaderText="User Assigned">
                            <ItemTemplate>  
                                <asp:TextBox ID="txt_UID" runat="server" Text='<%# Eval("UID")%>'
                                     Width="230px" BackColor="LightGoldenrodYellow"></asp:TextBox>
                                     <asp:HiddenField ID="hfUserId" runat="server" />
                            </ItemTemplate>
                            <ItemStyle Width="150px" />
                        </asp:TemplateField>
                    
                        <asp:CommandField ShowEditButton="false" >
                        <ItemStyle Font-Size="Smaller" ForeColor="#FF3300" />
                        </asp:CommandField>
                    </Columns>
                   
                </asp:GridView>

and here is my code for the javascript:

<script type="text/javascript">
       $(document).ready(function () {
           Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
           Sys.WebForms.PageRequestManager.getInstance().beginAsyncPostBack();
           function EndRequestHandler(sender, args) {
               $("[id*=txt_UID]").autocomplete({

                   source: function (request, response) {
                       $.ajax({
                           url: '<%=ResolveUrl("~/Service.asmx/GetUserNames") %>',
                           data: "{ 'prefix': '" + request.term + "'}",
                           dataType: "json",
                           type: "POST",
                           contentType: "application/json; charset=utf-8",
                           success: function (data) {
                               response($.map(data.d, function (item) {
                                   return {
                                       label: item.split('-')[0],
                                       val: item.split('-')[1]
                                   }
                               }))
                           },
                           error: function (response) {
                               alert(response.responseText);
                           },
                           failure: function (response) {
                               alert(response.responseText);
                           }
                       });
                   },
                   select: function (e, i) {
                       $("[id*=hfUserId]", $(e.target).closest("td")).val(i.item.val);
                   },
                   minLength: 1
               });
           }
       }); 
</script>