You could
- check values in PAI (AT SELECTION SCREEN ON)
- use a listbox for the parameter
- use a checkbox and from its value fill another field
Sample for reference
TYPE-POOLS: vrm. DATA: tab_values TYPE vrm_values, rcd_values LIKE LINE OF tab_values, variant_id TYPE vrm_id, oneorzero TYPE c. LOAD-OF-PROGRAM. rcd_values-key = '0'. rcd_values-text = '0'. APPEND rcd_values TO tab_values. rcd_values-key = '1'. rcd_values-text = '1'. APPEND rcd_values TO tab_values. PARAMETERS: dropdown TYPE n AS LISTBOX VISIBLE LENGTH 3 OBLIGATORY, checkbox AS CHECKBOX, checkaft TYPE c. AT SELECTION-SCREEN OUTPUT. variant_id = 'DROPDOWN'. CALL FUNCTION 'VRM_SET_VALUES' EXPORTING id = variant_id values = tab_values EXCEPTIONS OTHERS = 0. AT SELECTION-SCREEN ON checkbox. IF checkbox IS INITIAL. oneorzero = '0'. ELSE. oneorzero = '1'. ENDIF. AT SELECTION-SCREEN ON checkaft. IF checkaft NE '0' AND checkaft NE '1'. MESSAGE 'Invalid value' TYPE 'E'. ENDIF.
Regards,
Raymond