如何在進度4GL的CASE中編寫IF語句？

Question

我正試圖讓用戶有機會對圖像進行過濾。在我的代碼，我會收到一個字符串像

ASSIGN img = "images\green.png". 

我認爲這將是最好寫下面如果在一個CASE語句，但是我不知道怎麼了，因爲你不能使用類似火柴或任何CASE語句中的其他變量值。

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. 

所以我顯然不能寫這樣的：

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. 

任何想法還是我只是把它在IF語句？

Answer 1

這裏有一個小竅門，我們用它來把表達式case語句：

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.