set-data in list-box%

Sets the associated data for a list box choice item. See also append.

• (send a-list-box set-data n data) -> void
     n : exact non-negative integer
     data : value

  Sets the associated data for item indexed by n. List box items are indexed from 0. If n is equal to or larger than the number of choices, an exn:application:mismatch exception is raised.