filter information between two dates

Writw code in button click event
Use following query
SELECT bill.billno,convert(varchar, bill.bill_date,103), bp_master.bp_name FROM bill INNER JOIN bp_master ON bill.bp_id = bp_master.bp_id where bill.bill_date>='" + Convert.ToDateTime(dtfrom.Value.ToShortDateString()) + "' and bill.bill_date<='" + Convert.ToDateTime(dtto.Value.ToShortDateString()) + "'"