Identifies the item currently selected on the list, which is called an index. The values of this property range from -1 (minus one) to the total number of rows on the list minus one, that is, ListCount minus one. When no row is selected, this property returns -1 (minus one). When users select a row on this object, the system defines the value of this property. The value of this property on the first row of a list is 0 (zero), the value of the second row is 1 (one), and so on. This property cannot be changed while this object is active.