Data Grid

Question

I want to display items in Datagrid. I need to display 25 rows at a time. I want to use sort and paging features. I do not want to use default paging, because it will retrieve all records for each page. I want to retrieve first 25 records and display in the grid. I want to sort by a specific field. If user clicks another field to sort, then I want to start over again and display the first 25 records based on the new sort field. If user click the next button then I need to show the records from 25 to 50 based on the sort field selected. I have done the paging function to retrieve only 25 recods at a time, I am stubmled when I move to the sort function. Any / All ideas appericiated. Thanks Jijo.