I'm currently developing a time/Expense system in an access database. What I am trying to do is provide the user the ability to populate a form field if and only a prior form field is populated with the correct data.
I have two fields on my Expense form - 1 is a Expense code ID and the other is Mileage. What I want to do is if the expense form field has an expense ID related only to mileage (text string is Mileage), then and only then can they input the mileage amount but cannot enter anything in the Expense amount form field. And, vice versa, if the user enters the mileage (it auto populates the mileage amount based on an calculation), then they cannot enter anything in the Expense Amount field. See screen shot attached. Any help would be appreciated