[Mono-winforms-list] New to the list

Carlos Alberto Cortez calberto.cortez at gmail.com
Fri Sep 7 18:39:14 EDT 2007


> >
> Heh... yes, I have that feeling too. I just didn't want to made 
> design-level changes (and even if I did want, I didn't dare since this 
> is my first day with the winforms source code).
> However, I can explain how I see the problem so you guys decide if 
> deeper changes are necesary.
> The ListView problem:
> 1) When a new SubItem is added, the ListViewSubItem constructor sets the 
> SubItem text.
> 2) Text.set in the SubItem Text property calls Invalidate(Bounds).
> 3) Bounds.get calls GetBounds() and this calls GetItemLocation().
> 4) GetItemLocation() uses the items_location[] array.
> Now, items_location[] is set to an initial lenght of [16] by the 
> ListView constructor, and extended by AdjustItemsPositionArray if needed.
> AdjustItemsPositionArray is only called by CalculateListView, which is 
> called only before a redraw.
> So, if you add a 17th item before a redraw, you get an index out of 
> bounds at ListView.GetItemLocation().
> I think the problem here is that Invalidate() ends up usign 
> items_location[], which is only calculated when redrawing. That doesn't 
> seem to make sense sometimes, since Invalidate() happens _before_ the 
> redraw.

Actually the sequence is: Redraw () -> Invalidate () -> Update (Paint)

The thing is is that Redraw (and thus AdjustItemsPositionArray) is
_always_ called before Invalidate or Update (or Paint, which actually
requests Items count info and more). So this should be a problem

The problem anyway seems to be an out of synch state between them. The
problem is: I can't reproduce it.

Do you have a sample case? 


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