如何从组合框中获得选择的值作为变量PROGRESS 4GL

Question

在做任务时我遇到了问题，我不知道如何从组合框中获得值作为变量，我已经阅读了很多文档，但没有找到解决方案，也许你可以建议我。

DEFINE VARIABLE StateBox AS CHARACTER FORMAT "X(256)":U 
LABEL "Pick a Satete" 
VIEW-AS COMBO-BOX INNER-LINES 5 
DROP-DOWN-LIST
SIZE 16 BY 1 NO-UNDO.

DEFINE FRAME StateCombo
StateBox
WITH CENTERED ROW 4.

FOR EACH State NO-LOCK BREAK BY State.StateName:
StateBox:ADD-LAST(State.StateName) IN FRAME StateCombo. 
END.

vStateText = (SCREEN-VALUE:StateBox). //ERROR

ENABLE StateBox WITH FRAME StateCombo.
APPLY "VALUE-CHANGED" TO StateBox IN FRAME StateCombo.
WAIT-FOR WINDOW-CLOSE OF CURRENT-WINDOW. //COMBO-BOX CREATED

我尝试了SCREEN-VALUE, STREAM，我想得到一个解决方案

Answer 1

vStateText = (SCREEN-VALUE:StateBox). //ERROR

这很接近。SCREEN-VALUE是文档中的一个属性。引用属性的正确语法是先有句柄/事物，然后是属性。所以StateBox:SCREEN-VALUE应该是正确的顺序。

Answer 2

你应该

WAIT-FOR GO OF CURRENT-WINDOW.

就像Peter说的，它必须是StateBox:SCREEN-VALUE，不需要APPLY VALUE-CHANGED，所以这个就可以了:

ENABLE StateBox WITH FRAME StateCombo.
WAIT-FOR GO OF CURRENT-WINDOW. //COMBO-BOX CREATED
DEFINE VARIABLE vStateText AS CHARACTER NO-UNDO .
vStateText = (StateBox:SCREEN-VALUE). //ERROR
MESSAGE vStateText
VIEW-AS ALERT-BOX INFORMATION BUTTONS OK.

但是由于StateBox也是一个CHARACTER-Variable，所以您不需要额外的变量vStateText:

ENABLE StateBox WITH FRAME StateCombo.
WAIT-FOR GO OF CURRENT-WINDOW. //COMBO-BOX CREATED
ASSIGN StateBox .
MESSAGE StateBox
VIEW-AS ALERT-BOX INFORMATION BUTTONS OK.

不带=操作符的ASSIGN语句将把屏幕值赋给相同的命名变量。