[Qt-interest] Native Dialog crashes using QFileDialog

[Alexis Ménard]

On Tuesday 21 April 2009 18:06:01 Jan Wurster wrote:
>  Dear list,
>
>  To begin with - I know this is not (at least not directly) - Qt problem
> ;)
>
>  We've recently noticed that our application seems to crash in open file
> dialogs on certain machines when clicking on or even just hovering over
> media files.
>
>  The issue seems well known throughout the net, there's even a
> workaround available that 'fixes' the problem. One of many poor souls
> that ran into this issue posted here:
>
> http://club.cdfreaks.com/f32/windows-explorer-crashes-when-starting-avi-
> just-pointing-cursor-over-avi-f-126014/
>
>  Apparently media previewing / shmedia.dll is the culprit - or certain
> codecs that have problem handling unicode-formatted (?) requests from
> the windows API for previewing videos. Windows explorer itself doesn't
> crash (any more!) - it seems that the issue got fixed in a patch.
>
>  The workaround of course is to unregister shmedia.dll as follows:
>
> regsvr32 /u shmedia.dll
>
>  This always helped, any media files that previously led to the crash
> now wouldn't any more.
>
>  As we cannot easily enforce this on customer systems the questions
> remain:
>
>  - Is it at all possible - we're using the static methods of QFileDialog
> - to catch this
>    problem? My personal experience with the windows API is limited,
> unfortunately.
>
>  - Is there a way to disable media previewing via QFileDialog options?
> I've browsed the
>    documentation but didn't actually see anything in ViewMode or similar
> that related to
>    previews.
>

No since the non-native doesn't have this feature there is no such flag to 
control that on the native one as well. Qt as a standard user of the Windows 
API, just call functions that run the window file dialog. Qt has no control on 
it (unless giving parameters to the function) and i would say if it's buggy in 
the native one, fill a bug to Microsoft (i am pretty sure you can reproduce 
the bug without Qt at all (see qfiledialog_win.cpp to see how we call the 
native dialog) and cross your fingers perhaps in two or three years it will be 
fixed :D. Or use the non-native, you will have no previews so no crash :D.


>  Best regards,
> -.jan.-
>
>
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-- 

Alexis Ménard
Software Engineer, Widgets Team 1
Qt Software, Nokia Norge AS, Sandakerveien 116, 0484 Oslo, Norway
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