[Gambas-user] ListBox selection

[Demosthenes Koptsis]

Yes all of you have understood correctly what i want to do.

Of course Bad Index problem appears and for that i implement this code:


---------------------------------
Public Sub btnRemove_Click()

  Dim i As Integer
  Dim sSelected As New String[]

   sSelected.Clear
   
   For i = 0 To lstBox.Count - 1
     If lstBox[i].Selected Then
       sSelected.Add(lstBox[i].Text)
     Endif
   Next

   For i = 0 To sSelected.Count - 1
     lstBox.Remove(lstBox.Find(sSelected[i]))
   Next

End
---------------------------------

This code is based on selected text

lstBox.Remove(lstBox.Find(sSelected[i]))

thats why i wanted a lstBox[i].Index.

But i will try the DEC i code to see the deference.




On Wed, 2011-06-15 at 20:25 +0200, tobias wrote:
> hi,
> 
> oh well, now i think i understood. but this doesn't change my answer:
> you don't need find to get the index of a special item.
> you said, you selected one or multiple items and you want to remove 
> them. no problem, use the method i mentioned earlier in this topic:
> PUBLIC SUB Button1_Click()
> 
>    DIM i AS Integer
> 
>    'Go through all items and find those that are selected
>    FOR i = 0 TO ListBox1.Count - 1
>      IF ListBox1[i].Selected THEN
>        ListBox1.Remove(i)
>      ENDIF
>    NEXT
> 
> END
> 
> this code won't work properly, i saw while testing. (it raises "Bad 
> Index" - it's "out of bounds") thanks to Benoit's answer i understand 
> why. i iterate through all the indices until the initial ListBox1.Count 
> which has changed during processing. but shouldn't such a FOR-loop be 
> more dynamically? is this FOR-loop end point only evaluated at the 
> beginning? or do i miss something else here?
> why does the loop get into the iteration where the error is raised even 
> if the condition shouldn't be true? (btw i'm using gambas2.22)
> 
> anyway you may use this one instead:
> 
> DIM i AS Integer
> 
>    'Go through all items and find those that are selected in a while 
> which evaluates ListBox1.Count every iteration
>    i = 0
>    WHILE i < ListBox1.Count
>      'is it selected?
>      IF ListBox1[i].Selected THEN
>        'remove and...
>        ListBox1.Remove(i)
>        'don't forget to decrement i because the relative offset of the 
> next element has changed to the current offset, so one has to process 
> the current index again
>        DEC i
>      ENDIF
>      INC i
>    WEND
> 
> or did i still not get what you wanted?
> 
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-- 
Regards,
Demosthenes Koptsis.