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TYPE-POOLS:VRM.DATA: NAME TYPE VRM_ID.DATA:NUM TYPE I. "根据PRODH字段长度判断 某行属于哪一级DATA:LOADED TYPE C LENGTH 1."控制不重复查询数据库和不反复append数据 to WA1[]TYPES: BEGIN OF WA,   KEY(40),   TEXT(80) TYPE C, END OF WA.DATA:GT LIKE T179T OCCURS 0 WITH HEADER LINE.DATA:WA1 TYPE TABLE OF WA WITH HEADER LINE."111DATA:WA2 TYPE TABLE OF WA WITH HEADER LINE.                 "111222DATA:WA3 TYPE TABLE OF WA WITH HEADER LINE.                 "111222333DATA:ITAB LIKE T179T OCCURS 0 WITH HEADER LINE.DATA: PS_T(15) TYPE C.SELECTION-SCREEN BEGIN OF BLOCK T1 WITH FRAME TITLE TEXT-001.SELECTION-SCREEN BEGIN OF LINE.SELECTION-SCREEN COMMENT 1(31) TEXT-003.PARAMETERS: PL1 LIKE PS_T AS LISTBOX VISIBLE LENGTH 15 USER-COMMAND P1."一级类SELECTION-SCREEN END OF LINE.SELECTION-SCREEN SKIP 1.SELECTION-SCREEN BEGIN OF LINE.SELECTION-SCREEN COMMENT 1(31) TEXT-004.PARAMETERS: PL2 LIKE PS_T AS LISTBOX VISIBLE LENGTH 15 USER-COMMAND P2."二级类SELECTION-SCREEN END OF LINE.SELECTION-SCREEN SKIP 1.SELECTION-SCREEN BEGIN OF LINE.SELECTION-SCREEN COMMENT 1(31) TEXT-005.PARAMETERS: PL3 LIKE PS_T AS LISTBOX VISIBLE LENGTH 15."三级类SELECTION-SCREEN END OF LINE.SELECTION-SCREEN END OF BLOCK T1.INITIALIZATION.AT SELECTION-SCREEN OUTPUT.  NAME = 'PL1'.  IF LOADED  IS INITIAL.  SELECT *  FROM T179T INTO TABLE GT  WHERE SPRAS = 1.  LOADED = 'X'.  LOOP AT GT.    NUM = STRLEN( GT-PRODH ).    IF NUM = 5.      WA1-TEXT  = GT-VTEXT."Description      WA1-KEY   = GT-PRODH."Product hierarchy   key field      APPEND: WA1.    ENDIF.    CLEAR: GT,NUM,WA1."CLEAR 清空WA1工作区，不清空WA1[]内表  ENDLOOP.  ENDIF.  CALL FUNCTION 'VRM_SET_VALUES'    EXPORTING      ID     = NAME      VALUES = WA1[].AT SELECTION-SCREEN.  CASE SY-UCOMM.    WHEN 'P1'.      CLEAR: PL2,PL3.      "清空2、3级下拉空默认值，当用户在选择屏幕上重新选择时需要清除      CLEAR:WA2,WA2[].      "清空2级下拉内表对应的值，当用户在选择屏幕上重新选择时需要清除      CLEAR NUM.      LOOP AT GT .        NUM = STRLEN( GT-PRODH ).        IF NUM = 10 AND GT-PRODH+0(5) = PL1.          WA2-TEXT  = GT-VTEXT.          WA2-KEY   = GT-PRODH.          APPEND: WA2.        ENDIF.        CLEAR:GT,NUM,WA2.      ENDLOOP.      CALL FUNCTION 'VRM_SET_VALUES'        EXPORTING          ID     = 'PL2'          VALUES = WA2[].      CLEAR PL2.    WHEN 'P2'.      CLEAR PL3.      "清空3级下拉空默认值，当用户在选择屏幕上重新选择时需要清除      CLEAR:WA3,WA3[].      "清空3级下拉内表对应的值，当用户在选择屏幕上重新选择时需要清除      CLEAR NUM.      LOOP AT GT .        NUM = STRLEN( GT-PRODH ).        IF NUM = 18 AND GT-PRODH+0(10) = PL2.          WA3-TEXT  = GT-VTEXT.          WA3-KEY   = GT-PRODH.          APPEND: WA3.        ENDIF.        CLEAR:GT,NUM,WA3.      ENDLOOP.      CALL FUNCTION 'VRM_SET_VALUES'        EXPORTING          ID     = 'PL3'          VALUES = WA3[].      CLEAR PL3.  ENDCASE.