[DUG] TListitems disappearing and reappearing causing access violations

[Todd Martin]

Hi Ross

What a vague description of the problem.

It sounds like you program by mysticism more than logic. Despite what
you might believe, some or all of the objects in your listview have most
likely been destroyed and you're looking at random memory, where the
objects used to be.

In order to solve this problem, you need to isolate "where" every object
in your list is created and destroyed. Then use the debugger to find out
"when" those events occur. If the window is being destroyed and
re-created, where and when are those objects re-instantiated? Is this a
multi-threaded application?

Todd.

> Wondering if anyone has any ideas.
>
>  
>
> I've had this problem a long time from when I started writing an app
> about 7 or 8 years ago, but it happens so rarely it's not usually an
> issue. But one user in particularly is regularly sending me MadExcept
> reports which either have access violation errors or "the application
> appears to be frozen". In all cases it's during an access of a
> TListItem which was perfectly valid 10 lines of code up a procedure
> but suddenly doesn't exist.
>
>  
>
> The screenshot created at the same time shows the ListView has no
> visible items, but I know for a fact there are 30 or more items in the
> list. I believe sometimes the items visually disappear and reappear
> shortly afterwards, like a Desktop refresh.
>
>  
>
> I think I've heard something about Windows recreating the window
> handles or some such thing. I don't understand why it would do so.
> There are no changes to the listview that would require re-creating
> the window.
>
>  
>
> Any ideas?
>
>  
>
>
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-- 
/Fortune/ favours the *brave*
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