Add emptydatatext attribute on your gridview.
<asp:GridView ID="gvRedemptions" runat="server" AllowPaging="True" PageSize="50"
CellPadding="4" EmptyDataText="No record found." ForeColor="#333333" AutoGenerateColumns="false"
OnPageIndexChanging="gvRedemptions_PageIndexChanging" OnSelectedIndexChanged="gvRedemptions_SelectedIndexChanged"
Width="960px" AllowSorting="True" onsorting="gvRedemptions_Sorting">
Regards,
Eduard