How to display Row Number in GridView in ASP.Net

Just add the a new column in the GridView

<asp:TemplateField>
    <ItemTemplate>
        <%#(Container.DataItemIndex  + 1) %>
    </ItemTemplate>
</asp:TemplateField>

And dont add the value for this column

<asp:BoundField DataField="RowNumber" HeaderText="Row Number" />

and remove the above column also.