query extender control

Below is my coding on the query extender control... all working fine but if i want to show a prompt up message said if no record found?

what should i do ? how to do it ?

Coding(HolidaySearch.aspx)

<%@ Page Title="" Language="C#" MasterPageFile="~/SiteAdmin.Master" AutoEventWireup="true" CodeBehind="HolidaySearch.aspx.cs" Inherits="TimeAttendReport.Account.HolidaySearch" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
    <style type="text/css">
        .style3
        {
            width: 766px;
        }
        .style4
        {
            width: 100%;
        }
        .style5
        {
            width: 200px;
        }
        </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
    <div>
        <h2 style="color: Blue">
            Holiday Search:</h2>
    </div>
    <table class="style4">
        <tr>
            <td class="style5">
                Holiday Search:</td>
            <td>
                &nbsp;</td>
            <td>
                &nbsp;</td>
        </tr>
        <tr>
            <td class="style5">
                &nbsp;</td>
            <td>
                &nbsp;</td>
            <td>
                &nbsp;</td>
        </tr>
        <tr>
            <td class="style5">
                Holiday Name:</td>
            <td>
                <asp:TextBox ID="txtHoliday" runat="server" Height="22px" Width="221px"></asp:TextBox>
            </td>
            <td>
                &nbsp;</td>
        </tr>
        <tr>
            <td class="style5">
                &nbsp;</td>
            <td>
                <asp:Button ID="Button2" runat="server" Text="Search" />
            </td>
            <td>
                &nbsp;</td>
        </tr>
    </table>
      <div>
      <asp:GridView ID="GridView1" runat="server" AllowPaging="True" AllowSorting="True"
            AutoGenerateColumns="False" CellPadding="4" DataSourceID="LinqDataSource1"
            ForeColor="#333333" GridLines="None" PageSize="8" Width="531px" 
              style="text-align: center; background-color: #0000FF;">
            <AlternatingRowStyle BackColor="White" />
            <Columns>
                <asp:CommandField ShowDeleteButton="True" ShowEditButton="True" />
                <asp:BoundField DataField="ID" HeaderText="ID" SortExpression="ID" 
                    InsertVisible="False" />
                <asp:BoundField DataField="Holiday1" HeaderText="Holiday1" 
                    SortExpression="Holiday1" />
                <asp:BoundField DataField="Date" HeaderText="Date" SortExpression="Date" />
                <asp:BoundField DataField="State" HeaderText="State" SortExpression="State" />
            </Columns>
            <EditRowStyle BackColor="#2461BF" />
            <FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
            <HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
            <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
            <RowStyle BackColor="#EFF3FB" />
            <SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
            <SortedAscendingCellStyle BackColor="#F5F7FB" />
            <SortedAscendingHeaderStyle BackColor="#6D95E1" />
            <SortedDescendingCellStyle BackColor="#E9EBEF" />
            <SortedDescendingHeaderStyle BackColor="#4870BE" />
        </asp:GridView>
            <asp:LinqDataSource ID="LinqDataSource1" runat="server" 
              ContextTypeName="TimeAttendReport.App_Code.DataClasses1DataContext" 
              EnableDelete="True" EnableInsert="True" EnableUpdate="True" EntityTypeName="" 
              TableName="Holidays">
          </asp:LinqDataSource>
          <asp:QueryExtender ID="QueryExtender1" runat="server" TargetControlID="LinqDataSource1">
          <asp:SearchExpression DataFields="Holiday1" SearchType ="StartsWith"> 
          <asp:ControlParameter ControlID = "txtHoliday" />
          </asp:SearchExpression>
          </asp:QueryExtender>
            </div>
</asp:Content>