Re: Strange CComboBox::PresubclassWindow problem

From:

"AliR $VC++ MVP$" <AliR@online.nospam>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 9 May 2007 10:18:16 -0500

Message-ID:

<XFl0i.1672$UU.1304@newssvr19.news.prodigy.net>

Oh I just realized what you were saying. I misunderstood the dynamic
creation part.
It seems as though the combo box doesn't like getting calls to SetItemHeight
for list items in PreSubclassWindow when it is being created, I doesn't mind
SetItemHeight(-1,100).
Anyway, it's not an assert, it's a full blown exception. I tried catching
the excpetion to see what its complaining about couldn't, the only way I
could catch the exception was with catch(...) but I don't know if there is a
way to get execption information with the catch all method.

Anyway I really can think of a solution.

AliR.

"AliR (VC++ MVP)" <AliR@online.nospam> wrote in message
news:ypl0i.1668$UU.173@newssvr19.news.prodigy.net...

Try moving the call to after CComboBox::PreSubclassWindow()

AliR.

"Eric Margheim" <NOSPAM***eric@prism-grp.com***NOSPAM> wrote in message
news:exALIikkHHA.4628@TK2MSFTNGP06.phx.gbl...

I have a class derived from CComboBox. I override DrawItem to manipulate
the drawing of the list elements. For this to work I turn on
LBS_OWNERDRAWFIXED in the Create method style. For instances when the
control is actually in the dialog resource I explicitly set the parameters
in the properties. Simple enough.

I use SetItemHeight to configure the control. I have this in the Create
method for the cases when I dynamically create the control in a dialog. I
also have SetItemHeight code in PresubclassWindow for the cases when the
combobox control is part of a dialog resource.

My problem is that the SetItemHeight in PresublcassWindow is blowing on
an ASSERT (IsWindow(m_hWnd)) when the control is created dynamically.
m_hWnd is apparently bogus at this point. It shows "unused".

I can easily enough put some sort of bool member variable in Create that
tells me not to do SetItemHeight in PresubclassWindow, but that seems
like it might be a workaround for an underlying problem.

Can someone explain to me what's going on here?

Thanks

Eric