dropdown list by fast_excel

gistfile1.txt

module Libxlsxwriter
  class Validator < FFI::Struct
    layout :validate, :uint8,
           :criteria, :uint8,
           :ignore_blank, :uint8,
           :show_input, :uint8,
           :show_error, :uint8,
           :dropdown, :uint8,
           :value_number, :double,
           :value_formula, :string,
           :value_list, :pointer,
           :value_datetime, Datetime.by_value,
           :minimum_number, :double,
           :minimum_formula, :string,
           :minimum_datetime, Datetime.by_value,
           :maximum_number, :double,
           :maxmum_formula, :string,
           :maximum_datetime, Datetime.by_value,
           :input_title, :string,
           :input_message, :string,
           :error_title, :string,
           :error_message, :string
  end
  attach_function :worksheet_data_validation_range, :worksheet_data_validation_range, [Worksheet, :uint32, :uint16, :uint32, :uint16, Validator], :error
  module WorksheetWrappers
    def data_validation_range(row_begin, col_begin, row_end, col_end, rb_list)
      v = Libxlsxwriter::Validator.new
      v[:validate] = 5
      v[:criteria] = 0
      v[:show_input] = v[:show_error] = 0
      v[:dropdown] = 2
      sp = rb_list.map {|s| FFI::MemoryPointer.from_string(s)}
      sp << FFI::Pointer::NULL
      list = FFI::MemoryPointer.new(:pointer, sp.length)
      list.put_array_of_pointer(0, sp)
      v[:value_list] = list
      Libxlsxwriter.worksheet_data_validation_range(self, row_begin, col_begin, row_end, col_end, v)
    end
  end
end

tmp = Tempfile.open(['test', '.xlsx'])
book = FastExcel.open(tmp.path)
ws = book.add_worksheet('test_sheet')
ws.data_validation_range(1, 1, 100, 1, ['A', 'B', 'C'])
ws.write_value(row = 1, col = 1, 'AX')
ws.write_value(row = 2, col = 1, 'BX')
book.close
tmp.rewind
IO::binwrite('test.xlsx', tmp.read)
tmp.close!