Updating a dataset bound to a text box by program control

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data-binding

I have an application in which a grid and number of textboxes are bound to a dataset (the user interface is the bound textboxes).

While entering data manually is fine, I have a number of 'hidden' textbox fields I would like to update invisibly to the user by program control. I'm not sure of how to update these hidden textboxes and have the changed content propagated to the dataset.

At the moment, when the User updates the record, all his/manual changes are captured but not the program controlled hidden fields.

Is there an elegant way to do this beyond simulating a manual entry or using a focus change?