ABAP 如何实现屏幕字段不可输入

FORM LFILE_SFILE_DISPLAY.

  LOOP AT SCREEN.

    IF SCREEN-NAME = 'P_LFILE' .
      IF P_KUBUN = CNS_KEY_L.
        SCREEN-INPUT = 1.  "可输入
      ELSE.
        SCREEN-INPUT = 0.  "不可输入
      ENDIF.
    ENDIF.
    IF SCREEN-NAME = 'P_SFILE' .
      IF P_KUBUN = CNS_KEY_S.
        SCREEN-INPUT = 1.  "可输入
      ELSE.
        SCREEN-INPUT = 0.  "不可输入
      ENDIF.
    ENDIF.
    MODIFY SCREEN.

  ENDLOOP.

ENDFORM.                    "LFILE_SFILE_DISPLAY