ListIndex Property [Access 2003 VBA Language Reference]
You can use the ListIndex property to determine which item is selected in a list box or combo box. Read/write Long.
expression Required. An expression that returns one of the objects in the Applies To list.
The ListIndex property is an integer from 0 to the total number of items in a list box or combo box minus 1. Microsoft Access sets the ListIndex property value when an item is selected in a list box or list box portion of a combo box. The ListIndex property value of the first item in a list is 0, the value of the second item is 1, and so on.
The ListIndex property value is also available by setting the BoundColumn property to 0 for a combo box or list box. If the BoundColumn property is set to 0, the underlying table field to which the combo box or list box is bound will contain the same value as the ListIndex property setting.
List boxes also have a MultiSelect property that allows the user to select multiple items from the control. When multiple selections are made in a list box, you can determine which items are selected by using the Selected property of the control. The Selected property is an array of values from 0 to the ListCount property value minus 1. For each item in the list box the Selected property will be True if the item is selected and False if it is not selected.
The ItemsSelected collection also provides a way to access data in the selected rows of a list box or combo box.
To return the value of the ListIndex property, you can use the following:
Dim l As Long l = Forms(formname).Controls(controlname).ListIndex
To set the ListIndex property value, you can use the following:
Forms(formname).Controls(controlname).SetFocus Forms(formname).Controls(controlname).ListIndex = index
Where formname and controlname are the names of the form and list box or combo box control, respectively, expressed as String values, and index is the index value of the item.