Open a file with standard application from dialog

I have a file picker as a dialog control. The file name is to be used as 
part of a URL text field in Calc.

I'd like to have a quick look at the file content from within the dialog 
(some command button) to avoid mistakes. But the file can be of any sort 
(graphic, text, pdf, OpenDocument ...).

How can I open it with the graphical systems' standard application. I 
couldn't find a solution. It should work for Linux (openSUSE 11.3, KDE 
4.4.4) and if possible for Windows (XP or Vista), too.

I think it must be via some shell command as I find with my 
OpenOffice.org 3.2.1 (original version) that any links in OOo other than 
to OOo files are opened with the standard _browser_ (bug?).

Or is it a KDE (Windows ...) question?

Regards
Volker