using windows forms

currently wht i have fr binding the grid is

in form load i hve
sqlstr="
select p.id , p.pname ,0 as QTY, p.RATE, AMOUNT, p.dtfrm as From_DT,p.dtto as To_DT from PRDT left join M_customer C On C.Cid = t.cust_id left join M_prdt P On P.id = t.id where t.cust_id = " & dropdown1.SelectedValue & "
grid_trans.DataSource = ds1.Tables("trans")
grid_trans.AllowUserToAddRows = False
grid_trans.Columns(0).Visible = False


grid_trans.Columns(5).DefaultCellStyle.Format = DateFormat.ShortDate
grid_trans.Columns(6).DefaultCellStyle.Format = DateFormat.ShortDate



thios is how i bind the grid on the form load
from this tell me wht to do
need to format the above columns for accepting date