wxruby users - Mar 2009 - ListCtrl.get_selections broken?

Hi again,

may it be that ListCtrl.get_selections is broken? Or did I misunderstand
sth. in the docs?

I''m always getting 0 as the size of the returned array while
get_selected_item_count is reporting the correct number.

See the attachment or the following lines for a program that
demonstrates this.


require ''wx''
include Wx

class MyFrame < Frame
  def initialize
    super nil, -1, "ListCtrl Error"

    @list = ListCtrl.new(self, -1, DEFAULT_POSITION, DEFAULT_SIZE,
LC_REPORT)
    @list.insert_column(0, ''abc'')

    li = ListItem.new()
    li.set_state LIST_STATE_SELECTED

    li.set_text ''123''
    @list.insert_item(li)
    li.set_text ''234''
    @list.insert_item(li)
    li.set_text ''345''
    @list.insert_item(li)
    li.set_text ''456''
    @list.insert_item(li)


    puts @list.get_selected_item_count # --> 4
    puts @list.get_selections.size     # --> 0
  end
end

class MyApp < App
  def on_init
    f =  MyFrame.new
    f.show
  end
end

MyApp.new.main_loop


I hope I''m doing something wrong.

Cheers,
Christian.

Attachments:
http://www.ruby-forum.com/attachment/3407/ListCtrl_Err_demo.rb.rb

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Christian Schmidt wrote:
> I''m always getting 0 as the size of the returned array while
> get_selected_item_count is reporting the correct number.
>   
It works OK for me. I think the problem is the way you are adding items 
to the list.
>     @list = ListCtrl.new(self, -1, DEFAULT_POSITION, DEFAULT_SIZE,
> LC_REPORT)
>   
Note - this can be written ListCtrl.new(self, :style => LC_REPORT). You 
almost never need to use the clumsy ''DEFAULT_POSITION'',
''DEFAULT_SIZE''
etc. Use named arguments and these will be taken care of.
>     li = ListItem.new()
>     li.set_state 
>
>     li.set_text ''123''
>     @list.insert_item(li)
>     li.set_text ''234''
>     @list.insert_item(li)
>   
Your problem is here, I think. Each ListItem object represents a unique 
object in the list. The row it''s in is identified by an attribute
''id''.
However, you''re adding the same object multiple times. Do it like this 
instead, creating a new ListItem for each:

li = Wx::ListItem.new
li.state = LIST_STATE_SELECTED
li.id = 0 # For row 0
li.text = ''123''
@list.insert_item li

alex

Alex Fenton wrote:
> Note - this can be written ListCtrl.new(self, :style => LC_REPORT). You
> almost never need to use the clumsy ''DEFAULT_POSITION'',
''DEFAULT_SIZE''
> etc. Use named arguments and these will be taken care of.
This is great! I''ve always been annoyed by that, since I practically 
never need to explicitly set those using sizer based layout.
>>     li = ListItem.new()
>>     li.set_state 
>>
>>     li.set_text ''123''
>>     @list.insert_item(li)
>>     li.set_text ''234''
>>     @list.insert_item(li)
>>   
I didn''t use the ListItem helper-class in the original program. Just 
wanted to make it easier for you to reproduce the problem by selecting 
the items at startup. I was using @list.insert_item(pos,
''item'') and
@list.set_item(pos, col, ''property'') originally.
> Your problem is here, I think. Each ListItem object represents a unique
> object in the list. The row it''s in is identified by an attribute
''id''.
> However, you''re adding the same object multiple times. Do it like
this
> instead, creating a new ListItem for each:
> 
> li = Wx::ListItem.new
> li.state = LIST_STATE_SELECTED
> li.id = 0 # For row 0
> li.text = ''123''
> @list.insert_item li
I''ve been playing around with this now. I thought, it might also be a 
problem of references getting lost somewhere. So I modified it as 
follows:

    @li1 = ListItem.new()
    @li1.set_state LIST_STATE_SELECTED
    @li1.set_text ''123''
    @li1.id = 0
    @list.insert_item(@li1)

    @li2 = ListItem.new()
    @li2.set_state LIST_STATE_SELECTED
    @li2.id = 1
    @li2.set_text ''234''
    @list.insert_item(@li2)

    ...

But still no luck: get_selections.size == 0!

Christian.


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Christian - you didn''t say, but I''m assuming you''re
working on Windows
b/c I now tried it there and can reproduce the problem.

I''ve no idea why Windows differs here, but fortunately it''s
easy to fix.
The definition of get_selections is in Ruby and is in 
lib/wx/classes/listctrl.rb. If you want the definition that works on 
Windows, add something like this to your script:

class Wx::ListCtrl
  def get_selections
    selections = []
    item = get_next_item(-1, Wx::LIST_NEXT_ALL, Wx::LIST_STATE_SELECTED)
    while item >= 0
      selections << item
      item = get_next_item(item, Wx::LIST_NEXT_BELOW, 
Wx::LIST_STATE_SELECTED)
    end
    selections
  end
end

The only change is Wx::LIST_NEXT_ALL was previously LIST_NEXT_BELOW.

I''ll apply this to wxRuby once I''ve tested on other platforms.
Thanks
again for the report.

a

Hi Alex,

you''re right, I''m working on Win XP - hence your workaround
fixed it for
me.
Btw.: It''s me who has to thank you again for your great help!

Thank you for making wxRuby and also for providing such a great support!

Christian.


Alex Fenton wrote:
> Christian - you didn''t say, but I''m assuming
you''re working on Windows
> b/c I now tried it there and can reproduce the problem.
> 
> I''ve no idea why Windows differs here, but fortunately
it''s easy to fix.
> The definition of get_selections is in Ruby and is in
> lib/wx/classes/listctrl.rb. If you want the definition that works on
> Windows, add something like this to your script:
> 
> class Wx::ListCtrl
>   def get_selections
>     selections = []
>     item = get_next_item(-1, Wx::LIST_NEXT_ALL, Wx::LIST_STATE_SELECTED)
>     while item >= 0
>       selections << item
>       item = get_next_item(item, Wx::LIST_NEXT_BELOW,
> Wx::LIST_STATE_SELECTED)
>     end
>     selections
>   end
> end
> 
> The only change is Wx::LIST_NEXT_ALL was previously LIST_NEXT_BELOW.
> 
> I''ll apply this to wxRuby once I''ve tested on other
platforms. Thanks
> again for the report.
> 
> a
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