LIST BOX 联动的实现

有两种方式实现联动：
1、 USER-COMMAND
2、AT SELECTION-SCREEN ON VALUE-REQUEST FOR
listbox名称

例一：

REPORT zlm_listbox_02.

*&---------------------------------------------------------------------*

*&宏定义，填充下拉框

*&---------------------------------------------------------------------*

DEFINE fill_list.

value-key = &1. "个就是变量下拉框的值

value-text = &2. "这个是text

append value to &3.

END-OF-DEFINITION.

*&---------------------------------------------------------------------*

*&LIST-BOX 变量定义

*&---------------------------------------------------------------------*

TYPE-POOLS: vrm . "存放combobox内容的type pool

DATA: name TYPE vrm_id, " list box的名称

list_ctry TYPE vrm_values, " list box的值

list_city TYPE vrm_values, " list box的值

value LIKE LINE OF list_ctry . " list box的结构

*&---------------------------------------------------------------------*

*&屏幕定义

*&---------------------------------------------------------------------*

PARAMETERS: p_ctry TYPE char10 AS LISTBOX VISIBLE LENGTH 15 USER-COMMAND zctry.

PARAMETERS: p_city TYPE char10 AS LISTBOX VISIBLE LENGTH 15 USER-COMMAND zcity.

*&---------------------------------------------------------------------*

*&初始化

*&---------------------------------------------------------------------*

INITIALIZATION.

PERFORM zform_fill_ctry.

*&---------------------------------------------------------------------*

*&根据所选国家，显示城市

*&---------------------------------------------------------------------*

AT SELECTION-SCREEN.

CASE sy-ucomm.

WHEN 'ZCTRY'.

PERFORM zform_fill_city.

WHEN 'ZCITY'.

MESSAGE p_city TYPE 'I'.

WHEN OTHERS.

ENDCASE.

*&---------------------------------------------------------------------*

*& Form zform_fill_city

*&---------------------------------------------------------------------*

* text

*----------------------------------------------------------------------*

FORM zform_fill_city.

DATA:value LIKE LINE OF list_ctry . " list box的结构

READ TABLE list_ctry INTO value WITH KEY key = p_ctry.

REFRESH list_city.

IF value-key = 'CH'.

fill_list 'BJ' '北京' list_city.

fill_list 'TJ' '天津' list_city.

ENDIF.

IF value-key = 'EN'.

fill_list 'LD' '伦敦' list_city.

ENDIF.

IF value-key = 'US'.

fill_list 'LSJ' '洛杉矶' list_city.

fill_list 'HSD' '华盛顿' list_city.

ENDIF.

"调用函数显示listbox里面的值

CALL FUNCTION 'VRM_SET_VALUES'

EXPORTING

id = 'P_CITY' " PARAMETERS's Name

values = list_city.

ENDFORM. "zform_fill_city

*&---------------------------------------------------------------------*

*& Form zform_fill_ctry

*&---------------------------------------------------------------------*

* text 填充国家

*----------------------------------------------------------------------*

FORM zform_fill_ctry.

REFRESH list_ctry.

fill_list 'CH' '中国' list_ctry.

fill_list 'EN' '英国' list_ctry.

fill_list 'US' '美国' list_ctry.

"调用函数显示listbox里面的值

CALL FUNCTION 'VRM_SET_VALUES'

EXPORTING

id = 'P_CTRY' " PARAMETERS's Name

values = list_ctry.

ENDFORM. "zform_fill_ctry

例二：
变动很小
INITIALIZATION.

PERFORM zform_fill_ctry.

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_ctry.

PERFORM zform_fill_city.

或者
AT SELECTION-SCREEN OUTPUT .

PERFORM zform_fill_ctry.

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_ctry.

PERFORM zform_fill_city.

或者直接

AT SELECTION-SCREEN ON VALUE-REQUEST FOR p_ctry.

PERFORM zform_fill_ctry.

PERFORM zform_fill_city.

但是出现了个问题，
就是在我变动国家后，城市框还显示上传选择的城市的key值


BOX 联动的实现" TITLE="LIST BOX 联动的实现" />

一直没解决，哪位知道怎样解决，请留言，谢谢