Question

我试图让用户有机会过滤图像。在我的代码中，我将收到一个像

这样的字符串

ASSIGN img = "images\green.png".

我认为最好在CASE中编写以下IF语句，但我不知道如何，因为你不能在CASE语句中使用MATCHES或任何其他变量值。

IF img MATCHES "*green*" THEN DO:
    MESSAGE "It's green!"
        VIEW-AS ALERT-BOX INFO BUTTONS OK.
END.
ELSE IF img MATCHES "*orange*" THEN DO:
    MESSAGE "It's orange!"
        VIEW-AS ALERT-BOX INFO BUTTONS OK.
END.
ELSE IF img MATCHES "*red*" THEN DO:
    MESSAGE "It's red!"
        VIEW-AS ALERT-BOX INFO BUTTONS OK.
END.

所以我显然不能这样写：

CASE img:
    WHEN MATCHES "*green*" THEN DO:
        MESSAGE "It's green!"
            VIEW-AS ALERT-BOX INFO BUTTONS OK.
    END.
    WHEN MATCHES "*orange*" THEN DO:
        MESSAGE "It's red!"
            VIEW-AS ALERT-BOX INFO BUTTONS OK.
    END
    WHEN MATCHES "*red*" THEN DO:
        MESSAGE "It's red!"
            VIEW-AS ALERT-BOX INFO BUTTONS OK.
    END.
END CASE.

任何想法或者我只是把它留在IF声明中？

Answer 1

这里有一个小技巧，我们用它来将表达式放在case语句中：

CASE TRUE:
     WHEN img MATCHES "*green*" THEN DO:
          MESSAGE "It's green!"
             VIEW-AS ALERT-BOX INFO BUTTONS OK.
     END.
     WHEN img MATCHES "*orange*" THEN DO:
          MESSAGE "It's orange!"
             VIEW-AS ALERT-BOX INFO BUTTONS OK.
     END.
     WHEN img MATCHES "*red*" THEN DO:
          MESSAGE "It's red!"
             VIEW-AS ALERT-BOX INFO BUTTONS OK.
     END.
     OTHERWISE DO:
          MESSAGE "It's something else!"
             VIEW-AS ALERT-BOX INFO BUTTONS OK.
     END.
END CASE.

如何在CASE in Progress 4GL中编写此IF语句？

1 个答案: