Listview - how to update total column during insert or edit

Dear All,
I have a listview containing 3 texboxes (among others) txtQty, txtPrice, and txtTotal.
How do I update the value of the txtTotal during data entry (i.e. triggered when leaving txtPrice or txtQty during insertion or editing).
IThe select template is fine because I calculate it in my y select statement (select *,qty * price as [myTotal])
Thanks (again),
MDB
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