property Items.EnableItem(Item as HITEM) as Boolean

Returns or sets a value that determines whether a item can respond to user-generated events.

Item as HITEM A long expression that indicates the item's handle
Boolean A boolean expression that indicates whether the item is enabled or disabled.

Use the EnableItem property to disable an item. A disabled item looks grayed and it is selectable. Use the SelectableItem property to specify the user can select an item. Once that an item is disabled all the cells of the item are disabled, so CellEnabled property has no effect. To disable a column you can use Enabled property of a Column object.