make navigation dynamically in listview

Hi
i make list view in asp.net 
and want to dynamicallly from code behind , show 25 products  each page..and for other show navigation 
i.e. 1  2   3  4  5   6   7    8   etc....
so on 2 click, show 26 to 50...and so on..
i want to make navigation from code behind and static ....
for exp.. if 200 products are there,,
show 1 to 25 , then navigation for  as :
1      2    3   4    5     6      7      8

I used 
<asp:DataPager runat="server" ID="ItemDataPager" PageSize="25"> <Fields> <asp:NumericPagerField ButtonCount="5" /> </Fields> </asp:DataPager>
but this is static ..how to make dynamic ...
how to do this