# Stuck noobie: XRC/xrcise woes

**URL:** <https://www.ruby-forum.com/t/stuck-noobie-xrc-xrcise-woes/190533>\
**Category:** wxRuby\
**Created:** [June 22, 2010, 9:27am UTC](https://www.ruby-forum.com/t/stuck-noobie-xrc-xrcise-woes/190533 "2010-06-22T09:27:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jdunneuk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/35a633/32.png) [@jdunneuk](https://www.ruby-forum.com/u/jdunneuk)\
**Post date:** [June 22, 2010, 9:27am UTC](https://www.ruby-forum.com/t/stuck-noobie-xrc-xrcise-woes/190533/1 "2010-06-22T09:27:41Z")

</div>

Hi,

I’m teaching myself to use wxRuby and DialogBlocks to create a front end  
for a Ruby program I wrote. And I’m hopelessly stuck!

In DialogBlocks (or indeed wxFormBuilder, which gives me the same  
problem) I can create a widget, give that widget a new id and class name  
(in the example I created below, text\_box1 and CaseChangeTextCtrl1,  
respectively), and then add a module which utilises that widget in my  
program, no problem.

But the moment I try to add a second widget with a second id and a  
second class, (in the example below, text\_box2 and CaseChangeTextCtrl2 )  
I get an “uninitialized constant” error for that widget when I run my  
program. I don’t understand it at all. The two widgets are the same,  
except they have different class names and different id names.

Is there some limit (a limit of 1) to the number of classes you can  
create in an XRC file or xrcise-generated rb file? Do you have to get  
DialogBlocks to create separate files for each new class apart from the  
first class, or something?

I am sure I am missing something simple. But I have spent hours on this,  
and can’t figure it out. Please! Help! Me!

warm regards

John

Below is everything in the chain: 1) the xrc file created by  
dialogblocks; 2) the rb file generated from that xrc file by xrcise  
(this is the file that produces the error); 3) the user-written code (in  
this case, an exercise taken from the web) that calls that  
xrcise-generated rb file; and 4) the error message.

1. 

###### the xrc file
\<?xml version="1.0" encoding="UTF-8"?\>

;  
  
wxCAPTION|wxRESIZE\_BORDER|wxSYSTEM\_MENU|wxCLOSE\_BOX  
400,300  
From Scratch  
1  
  
wxVERTICAL  
  
wxGROW|wxALL  
5  
1  
  
wxTE\_MULTILINE  
  
  
  
wxALIGN\_CENTER\_HORIZONTAL|wxALL  
5  
  
Upper  
  
  
  
wxALIGN\_CENTER\_HORIZONTAL|wxALL  
5  
  
Lower  
  
  
  
wxGROW|wxALL  
5  
1  
  
wxTE\_MULTILINE

1. 

######## the ruby file generated by xrcise ######

# This class was automatically generated from XRC source. It is not

# recommended that this file is edited directly; instead, inherit from

# this class and extend its behaviour there.

# 

# Source file: exercise.xrc

# Generated at: Tue Jun 22 16:49:12 +1000 2010

class TextFrameBase \< Wx::Frame

```
 attr_reader :text_box1, :upper_bt, :lower_bt, :text_box2

 def initialize(parent = nil)
      super()
      xml = Wx::XmlResource.get
      xml.flags = 2 # Wx::XRC_NO_SUBCLASSING
      xml.init_all_handlers
      xml.load("exercise.xrc")
      xml.load_frame_subclass(self, parent, "ID_WXFRAME")

      finder = lambda do | x |
           int_id = Wx::xrcid(x)
           begin
                Wx::Window.find_window_by_id(int_id, self) || int_id
           # Temporary hack to work around regression in 1.9.2;

```

remove  
# begin/rescue clause in later versions  
rescue RuntimeError  
int\_id  
end  
end

```
      @text_box1 = finder.call("text_box1")
      @text_box1.extend(CaseChangeTextCtrl1)
      @upper_bt = finder.call("upper_bt")
      @lower_bt = finder.call("lower_bt")
      @text_box2 = finder.call("text_box2")
      @text_box2.extend(CaseChangeTextCtrl2) #<<<<< THIS IS THE BAD

```

LINE THAT CAUSES THE ERROR  
if self.class.method\_defined? “on\_init”  
self.on\_init()  
end  
end  
end

1. 

######## Exercise.rb ########  
require ‘rubygems’  
require ‘wx’

# load in the generated code

require ‘my\_frame’

# Mix-in for a Wx::TextCtrl

module CaseChangeTextCtrl1

# convert all the text in the control to upper case

def upcase!  
self.value = self.value.upcase  
end

# convert all the text in the control to lower case

def downcase!  
self.value = self.value.downcase  
end  
end

# Inherit from the generated base class and set up event handlers

class CaseChangeFrame \< TextFrameBase  
def initialize  
super  
evt\_button(upper\_bt) { text\_box1.upcase! }  
evt\_button(lower\_bt) { text\_box1.downcase! }  
end  
end

# Run the class

Wx::App.run do  
CaseChangeFrame.new.show  
end

1. 

##### ERROR MESSAGE:

R:\GUI\Practice\Exercise\>ruby Exercise.rb  
./my\_frame.rb:37:in `initialize': uninitialized constant TextFrameBase::CaseChangeTextCtrl2(NameError) from Exercise.rb:21:in`initialize’  
from Exercise.rb:29:in `new' from Exercise.rb:29:in`on\_init’  
from  
C:/Ruby187/lib/ruby/gems/1.8/gems/wxruby-2.0.1-x86-mingw32/lib/wx/classes/app.rb:16:in  
`main_loop' from C:/Ruby187/lib/ruby/gems/1.8/gems/wxruby-2.0.1-x86-mingw32/lib/wx/classes/app.rb:16:in`run’  
from Exercise.rb:28

---

<div class="post-metadata">

**Author:** ![jdunneuk](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/35a633/32.png) [@jdunneuk](https://www.ruby-forum.com/u/jdunneuk)\
**Post date:** [June 22, 2010, 9:44am UTC](https://www.ruby-forum.com/t/stuck-noobie-xrc-xrcise-woes/190533/2 "2010-06-22T09:44:20Z")

</div>

Dont worry. Figured it out. I was writing empty modules for the new  
classes, thinking that would suffice as I went along, but I need to put  
some placeholder functions into them.

cheers

John