suppose DataGrid named dgCustomize, insert the following code to the first column.
< asp:TemplateColumn HeaderText ="No." > < ItemStyle HorizontalAlign ="Center" ></ ItemStyle > < ItemTemplate > < asp:Label runat ="server" Text ='<%# dgCustomize.CurrentPageIndex*dgCustomize.PageSize+dgCustomize.Items.Count+1 % >'> </ asp:Label > </ ItemTemplate > </ asp:TemplateColumn >