I have a combo box on my form where the list is dynamically changed. The data entered must be in the list. I have set the limit to list property to true and this works fine if the user is entering the data. However, there are cases where the combo box choice is made automatically (the user enters a lookup value, which is generated into an account number, which becomes the combo box value). In this scenario, an invalid account number can be generated and made the value of the combobox without triggering an error.

How can I verify that the value generated exists in the combo box list before continuing?