Data Controls :: Filtering Data And Displaying In GridView Using TextBox

I have dropdown for height and age and a checkedlistbox  for city this controls are populated with data from db.i have a gridview with checkcontrol column after selection of height , age and city the gridview shld get populated with the filtered data from master table and on checkbox selection the selected row shld get inserted to the table. Currently I have a select stmt...

select * from mtbl where height between drpheight.selectedvalue and
drptoheight.selectedvalue and age between frmage.selectedvalue and
toage.selectedvalue and city in(............)
foreach (ListItem listItem in chkcity.Items) {
if (listItem.Selected == true) {
} }

after selecting multiple items how do i query for city ?