TextChanged Event in MS Access

Is there a way in in MS Access to detect a changed TextBox value where the TextBox's controlsource is e.g. =[txtSubTotal]-[txtDiscount]?

The TextBox is Locked=No, Enabled=Yes but obv开发者_如何学Pythoniously cannot be directly edited by the user since it is a calculated field.

What I'm looking for is the something like the Winforms TextChanged event but the nearest equivalents in Access appear to be AfterUpdate and Change and neither of those are firing when my TextBox's value changes.

Currently working in Access 2003, though this may change.

As the name update implies, this event will fire when data is updated into the tables.

As there is no update (to the tables) for your calculated control, no after or before update event will fire.

You have to write the event handers for the controls where the data is changed.