Sets or gets the column used in the sort process. If a combo box has more than one column, then you can set the SortColumn property to sort after the second column for example. The first column has 0 as index, the second one 1 ... This property has no effect if the Sorted property is set to false.
Warning: you cannot set this property if the combo box already contains items. Doing this will cause an exception(containing a string).
Return value:
Returns the index of the column used in the sort process.