Row Number in GridView

<asp:GridView ID="grd_Select" runat="server" AutoGenerateColumns="False" Width="100%" CssClass="mGrid" >

<Columns>

<asp:TemplateField HeaderText="SNo">

<ItemTemplate>

<%# Container.DataItemIndex + 1 %>

</ItemTemplate>

</asp:TemplateField>

<asp:BoundField DataField="User_Id" HeaderText="UserID" />

</Columns>

</asp:GridView>