>HI Nadya,
>Thank you for jumping in. Here is the code :

I assume, you have multiselect listbox. Ok, I would sligthly change this code, though don't think, it would make much difference.
>

 thisform.lockscreen=.t.
>LOCAL nRow, lnResult
>lnResult=0
>FOR nRow = 1 to This.ListCount
>	IF This.Selected(nRow)  THEN
>		lnResult=m.lnResult+VAL(This.List(nRow,2))
>	ENDIF
>NEXT nRow
>thisform.txtTotalValue.value=m.lnResult && Put here the name of textbox
 thisform.lockscreen=.f.

>I tried to put it in the When Event with the same results than in the Cklick() event.
>
>Thank you,
>Christian Cote