Generating Serial Number Inside Gridview with Pagingin asp.net

<asp:TemplateField HeaderText="SNo">

<HeaderStyle CssClass="DetailsContent" />
<ItemStyle Width="6%" Height="18px"  HorizontalAlign="Center" CssClass="DetailsContent"></ItemStyle>
<ItemTemplate>
                         
</ItemTemplate>
</asp:TemplateField>


// Code in Gridview_RowdataBound    protected void gvUserList_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            e.Row.Cells[0].Text = "" + ((((GridView)sender).PageIndex * ((GridView)sender).PageSize) + (e.Row.RowIndex + 1));
        
        }

    }