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我用MrEd Designer爲Scheme程序製作了一個用戶界面。它包含一個使用draw-point
繪製點的mred:canvas%。它的定義爲:mred中缺少方法:canvas%?
(define (naca-ui-init
{...}
#:airfoil-canvas-class
(airfoil-canvas-class canvas%)
{...})
及更高版本:
(set! airfoil-canvas
(new
airfoil-canvas-class
(parent vertical-pane-2165)
(horiz-margin 0)
(min-width 350)
(vert-margin 0)
(gl-config #f)
(stretchable-width #t)
(enabled #t)
(stretchable-height #t)
(min-height 175)
(label "Canvas")
(style '(border))))
當我嘗試(send airfoil-canvas draw-point 15 30)
,但是,我得到:
send: no such method: draw-point for class: canvas%
=== context ===
/usr/local/lib/racket/collects/racket/private/class-internal.rkt:4543:0: obj-error
/home/jason/NACA/naca-ui.scm:29:8: plot-point
/home/jason/NACA/naca.scm:225:23
/home/jason/NACA/naca-ui.scm:21:10: inner
我是誤讀documentation,還是有別的東西我不在這裏?
PS:可以有人有更多的代表添加標籤MrEd?這在這裏是相關的,但你需要1500來添加新的標籤。
如果你在這裏沒有得到答案,你應該試試[球拍郵件列表](http://racket-lang.org/community.html)。 – 2010-07-27 06:17:43
完成。如果我在那裏得到了很好的答案,我會在這裏總結一下。 – JasonFruit 2010-07-27 15:52:52