How to display a message when GridView isn't populated - asp.net

Question

I'm building a GridView based on what is passed on the previous page querystring.
Is there a way to display a message saying 'no records found' if the GridView isn't populated? i.e. the query produces no records to populate the GridView.
code:
<div class="centergrid">
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="SqlDataSource1" CssClass="bookgridview">
<Columns>
<asp:TemplateField HeaderText="Choose">
<ItemTemplate>
<asp:HyperLink ID="lnkSelect" runat='server' NavigateUrl='<%# String.Format("~/bookingform.aspx?ID={0}", Eval("ScheduleId")) %>'>Book</asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="TName" HeaderText="Name" SortExpression="TName" />
<asp:BoundField DataField="SDate" HeaderText="Date" SortExpression="SDate" DataFormatString="{0:d}" />
<asp:BoundField DataField="STime" HeaderText="Time" SortExpression="STime" />
<asp:BoundField DataField="TPriceadult" HeaderText="Price (Adult)"
SortExpression="TPriceadult" DataFormatString="{0:C}" />
<asp:BoundField DataField="TPricesenior" HeaderText="Price (Student/Senior)"
SortExpression="TPricesenior" DataFormatString="{0:C}" />
<asp:BoundField DataField="TPricechild" HeaderText="Price (Child)"
SortExpression="Tpricechild" DataFormatString="{0:C}" />
<asp:BoundField DataField="TDuration" HeaderText="Duration"
SortExpression="TDuration" />
<asp:BoundField DataField="ScheduleId" HeaderText="ScheduleId"
SortExpression="ScheduleId" Visible="False" />
</Columns>
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:ChinatowndbConnString %>"
SelectCommand="SELECT * FROM [vwSchedule] Where TourId=#tid">
<SelectParameters>
<asp:QueryStringParameter DbType="Int32" Name="tid" QueryStringField="tourid" />
</SelectParameters>
</asp:SqlDataSource>

Answer 1

Is there a way to display a message saying 'no records found' if the
GridView isn't populated?
Yes, with the EmptyDataTemplate.
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="SqlDataSource1" CssClass="bookgridview">
<emptydatarowstyle backcolor="LightBlue"
forecolor="Red"/>
<emptydatatemplate>
<asp:image id="NoDataImage"
imageurl="~/images/Image.jpg"
alternatetext="No Image"
runat="server"/>
No records found.
</emptydatatemplate>
<Columns>
<asp:TemplateField HeaderText="Choose">
<ItemTemplate>
<asp:HyperLink ID="lnkSelect" runat='server' NavigateUrl='<%# String.Format("~/bookingform.aspx?ID={0}", Eval("ScheduleId")) %>'>Book</asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="TName" HeaderText="Name" SortExpression="TName" />
<asp:BoundField DataField="SDate" HeaderText="Date" SortExpression="SDate" DataFormatString="{0:d}" />
<asp:BoundField DataField="STime" HeaderText="Time" SortExpression="STime" />
<asp:BoundField DataField="TPriceadult" HeaderText="Price (Adult)"
SortExpression="TPriceadult" DataFormatString="{0:C}" />
<asp:BoundField DataField="TPricesenior" HeaderText="Price (Student/Senior)"
SortExpression="TPricesenior" DataFormatString="{0:C}" />
<asp:BoundField DataField="TPricechild" HeaderText="Price (Child)"
SortExpression="Tpricechild" DataFormatString="{0:C}" />
<asp:BoundField DataField="TDuration" HeaderText="Duration"
SortExpression="TDuration" />
<asp:BoundField DataField="ScheduleId" HeaderText="ScheduleId"
SortExpression="ScheduleId" Visible="False" />
</Columns>
</asp:GridView>
Alternatively, you can use the built-in UI for the empty data row by setting the EmptyDataText property instead of this property.