DataGrid Item auto-generate serial number

when AllowPaging =False

< asp:DataGrid id = " DataGrid1 "  runat = " server " >
     < Columns >
      < asp:TemplateColumn >
       < ItemTemplate >
        <% # Container.ItemIndex  +   1 %>
       </ ItemTemplate >
      </ asp:TemplateColumn >
     </ Columns >
  </ asp:DataGrid >

or

< asp:DataGrid id = " DataGrid1 "  runat = " server " >
     < Columns >
      < asp:TemplateColumn >
       < ItemTemplate >
        <% #  this .DataGrid1.Items.Count  +   1 %>
       </ ItemTemplate >
      </ asp:TemplateColumn >
     </ Columns >
  </ asp:DataGrid >

AllowPaging ="True"

< asp:DataGrid id = " DataGrid1 "  runat = " server "  AllowPaging = " True " >
     < Columns >
      < asp:TemplateColumn >
       < ItemTemplate >
        <% #  this .DataGrid1.CurrentPageIndex  *   this .DataGrid1.PageSize  +  Container.ItemIndex  +   1 %>
       </ ItemTemplate >
      </ asp:TemplateColumn >
     </ Columns >
</ asp:DataGrid >

Reverse order:
//have been defined:
private int RowsCount = ds.Tables[0].Rows.Count

asp:DataGrid id = " DataGrid1 "  runat = " server "  AllowPaging = " True " >

                             < Columns >

                                    < asp:TemplateColumn >

                                           < ItemTemplate >

                                                  <% # RowsCount  -  DataGrid1.CurrentPageIndex  *  DataGrid1.PageSize  -  Container.ItemIndex  %>

                                           </ ItemTemplate >

                                    </ asp:TemplateColumn >

                             </ Columns >

                      </ asp:DataGrid >