selection of one item from ASP.Net ListBox

sorry for the frequent changes but as said had complications with javascript & updatepanel

so needed to chnage frequentluy

now reg the listbox selection issue of retaining the selection when displayed again

earlier i was storing the data in  table & making the stored items selected true

but now i am saving the values in a session

the values stored in session  wuld be like

where 1=1 AND name like 'A%' AND CITY in('MUM','DELHI')

from this how do  i keep the items selected