property Items.Selection as Variant
Selects items by index.

TypeDescription
Variant A long expression that indicates the index of item being selected, if the SingleSel property is True, or a safe array that holds a collection of index of items being selected, if the SingleSel property is False.
The Selection property selects/unselects items by index. Use the SelectItem property to select an item giving its handle. The ItemPosition property gives the relative position, or the position of the item in the child items collection. Use the SelectPos property to select items by position. The SelectPos property selects an item giving its general position.  

The SingleSel property specifies whether the control supports single or multiple-selection. Based on the SingleSel property the Selection value is: