refresh datapager in asp.net o n checkbox "onselectedindexchange"

I have used listview and asp:DataPager .. and use checkbox
<div class="pre-action-link" id="premain0" width="100%"> Collapse | Copy Code</div> OnSelectedIndexChanged ..    for exp. i have 300 records in listview which are distributed using datapager into 25 on each page.when i click on 3 page it shows records 75 to 100 .. then when i click on checkbox , it filters listview and has only 10 records .. but the datapager position remains at 3 (75 to 100 records) ..   how to clear it when checkbox onselectedindexchange called .. < ...