Automatically Generate Sr. No. in Gridview

<asp:TemplateField HeaderText="S No.">
                    <ItemStyle HorizontalAlign="Center" Width="50px" />
                    <ItemTemplate>
                        <asp:Label ID="Sno" runat="server" Text='<%# CType(Container, GridViewRow).RowIndex + 1%>'></asp:Label>
                    </ItemTemplate>
                    <HeaderStyle HorizontalAlign="Left" Width="35px" />
                </asp:TemplateField>