NotInList Event
The NotInList event occurs when the user enters a value in the text box portion of a combo box that isn't in the combo box list.
Remarks
The NotInList event applies only to controls on a form, not controls on a report.
To run a macro or event procedure when this event occurs, set the OnNotInList property to the name of the macro or to [Event Procedure].
This event enables the user to add a new value to the combo box list.
The LimitToList property must be set to Yes for the NotInList event to occur.
The NotInList event doesn't trigger the Error event.
The NotInList event occurs for combo boxes whose LimitToList property is set to Yes, after you enter a value that isn't in the list and attempt to move to another control or save the record. The event occurs after all the Change events for the combo box.
When the AutoExpand property is set to Yes, Microsoft Access selects matching values in the list as the user enters characters in the text box portion of the combo box. If the characters the user types match the first characters of a value in the list (for example, the user types "Smith" and "Smithson" is a value in the list), the NotInList event will not occur when the user moves to another control or saves the record. However, the characters that Microsoft Access adds to the characters the user types (in the example, "son") are selected in the text box portion of the combo box. If the user wants the NotInList event to fire in such cases (for example, the user wants to add the new name "Smith" to the combo box list), the user can enter a SPACE, BACKSPACE, or DEL character after the last character in the new value.
When the LimitToList property is set to Yes and the combo box list is dropped down, Microsoft Access selects matching values in the list as the user enters characters in the text box portion of the combo box, even if the AutoExpand property is set to No. If the user presses ENTER or moves to another control or record, the selected value appears in the combo box. In this case, the NotInList event will not fire. To allow the NotInList event to fire, the user should not drop down the combo box list.