Returns the index where dropped data should be placed in the
list. Interpretation of the value depends on the drop mode set on
the associated component. If the drop mode is either
DropMode.USE_SELECTION
or
DropMode.ON
,
the return value is an index of a row in the list. If the drop mode is
DropMode.INSERT
, the return value refers to the index
where the data should be inserted. If the drop mode is
DropMode.ON_OR_INSERT
, the value of
isInsert()
indicates whether the index is an index
of a row, or an insert index.
-1
indicates that the drop occurred over empty space,
and no index could be calculated.
Returns:
the drop index