windows phone 8 - Longlist selector with Checkboxes -

i developing app in windows phone 8 , using lls data template..

            <phone:longlistselector name="longlist">                 <phone:longlistselector.itemtemplate>                     <datatemplate>                     <checkbox ischecked="{binding property1, mode=twoway}" content="hii" checked="checkbox_checked_1" unchecked="checkbox_unchecked_1"/>                     </datatemplate>                 </phone:longlistselector.itemtemplate>             </phone:longlistselector>          </grid> 

while checked 1 , scroll list checkbox selection changed suppose select first shows me 2 selected or no-one selected means behave differently..i using code in .cs in link...

http://pastie.org/7938678 please suggest me how can rid off problem..

that design. tapped check box inside list item, thereby selecting it.

i suggest don't rely on list selection position changed, use event tap instead in datatemplate drive actions have based on list item.