Re: Common File Dialog and Extensions (SOLVED)

I think that the difference in what OP does is that you set the (long)
extension using CFileDialog constructor (which in turn passes the default
extension LPCTSTR to OPENFILENAME.lpstrDefExt), instead the OP is using
CFileDialog::SetDefExt(), which in turn calls SendMessage to send a
CDM_SETDEFEXT message with extension string passed as lParam.

Maybe this CDM_SETDEFEXT is the problem...

Moreover, I think that there is a documentation bug in OPENFILENAME at
MSDN:

OPENFILENAME Structure
http://msdn.microsoft.com/en-us/library/ms646839.aspx

<quote>
lpstrDefExt
[...]
This string can be any length, but only the first three characters are
appended.
</quote>

The above MSDN sentence is clearly worng, as your code snippet shows (in
fact, the "abcd" 4-character extension is managed correctly and is not
truncated).

If you confirm that, maybe someone could fill a documentation bug in the
Community Content section of that MSDN page.

Giovanni