Help with Update after Error Checking

[Russell]

I have a form that I want to ensure all relevant fields are completed prior to appending the new dataset to the table.

Data set update works fine, as does the error checking using:

IF IsNull(Controlname) Then
'Error Message
Else IF
'Next control check
End IF



Form submission is via an "onclick" event of an image rather than a button (trying to make things pretty).

My problem if someone then updates the field, but doesn't exit or tab out of the field, then my form doesn't know that it has been updated.
Any ideas on how to either force a "tab" or how to force exit from the field?

Thanks

[June7]

Could set field as required in table design and let Access nag users. They'll eventually learn that entering data avoids error message.

Can also use control's ValidationRule and ValidationText properties.

I did a test of editing a field then clicking a command button without first leaving field. The form definitely knows that field has been edited.