property Items.CellData(Index as Long, ColIndex as Variant) as Variant
Retrieves or sets a value that indicates the extra data for a specific cell.

TypeDescription
Index as Long A long expression that indicates the index of the item.
ColIndex as Variant A long expression that indicates the column's index or a string expression that indicates the column's name.
Variant A VARIANT expression that indicates the cell's extra data.

Use the CellData to associate an extra data to your cell. Use ItemData when you need to associate an extra data with an item. The CellData value is not used by the control, it is only for user use. Use the Data property to assign an extra data to a column.