error trapping on subform

[Guest]

I am trying to error trap on a subform so after a date is filled a set number
of fields on the same record line need to be filled in otherwise the box will
be cleared and the required fileds highted in red.

I have achieved this for when on a single view form but cannot when there
are multilpe records in the subform linked the main?

 

[Guest]

You can use the BeforeUpdate event of the sub form to check if all the values
are filled, if not prompt a message

If IsNull(Me.[TextBoxNAme]) Then
MsgBox "Field must be filled"
Cancel = True ' process will be stoped
End If