TkEntry - input prevention question

ruby-talk
1

How do I prevent a keystroke from even updating an entry? My current
solution is:

e.bind_append(“KeyRelease”) {e.value = e.value.gsub(/\D/, “”)}
e.bind_append(“Key”) {e.value = e.value.gsub(/\D/, “”)}

which gives the desired end result, but the character still appears
before being removed…

~Me!

2

Hi,

···

From: mhm26@drexel.edu (matt)
Subject: TkEntry - input prevention question
Date: Fri, 30 Apr 2004 12:49:02 +0900
Message-ID: 13383d7a.0404291947.58120dd8@posting.google.com

How do I prevent a keystroke from even updating an entry? My current
solution is:
e.bind_append(“KeyRelease”) {e.value = e.value.gsub(/\D/, “”)}
e.bind_append(“Key”) {e.value = e.value.gsub(/\D/, “”)}
which gives the desired end result, but the character still appears
before being removed…

If your Tcl/Tk suppors validatecommand option for entry widgets,
please use the option (see the sample ‘entry3.rb’ of widget demos
included in the Ruby source archive).
If not, the following script is an example.

require ‘tk’

e = TkEntry.new.pack
e.bind(‘Key’, proc{|key| Tk.callback_break if key =~ /\D/}, ‘%K’)

Tk.mainloop

Tk.callback_break can break callback operations of the event.

                              Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)