Re: Using SHGetFileInfo causes Assertion

From:
"AliR \(VC++ MVP\)" <AliR@online.nospam>
Newsgroups:
microsoft.public.vc.mfc
Date:
Fri, 17 Apr 2009 11:42:50 -0500
Message-ID:
<bl2Gl.27213$yr3.8797@nlpi068.nbdc.sbc.com>
Did you find the problem? and Fix it?

What does if (!ref_listCtrl) actually do? What type is ref_listCtrl. If
you are trying to check that it has a valid handle then you might want to do
this instead:

if (!ref_listCtrl.IsWindow())
{
    return FALSE;
}

When you call Detach it simply detaches the handle associated with the image
list and returns the handle. If you are supposed to despose of the handle
then it will leak if you don't destroy the object represented by the handle.

Make sure you understand the difference between DeleteObject and Detach
method of CGdiObject.

AliR.

"newgroupsurfer" <newsgroupsurfer@yahoo.com> wrote in message
news:e67349ff-cf84-48b7-b07a-340541c81ab4@h28g2000yqd.googlegroups.com...
On Apr 16, 11:59 am, "AliR \(VC++ MVP\)" <A...@online.nospam> wrote:

When the assert comes up hit Retry. That should take to the line with the
ASSERT on it.

Are you sure that your listcontrol has a valid handel when you are calling
your method?


Yes after reading these comments I added the following lines to test
if the ListCtrl does have a valid handle. It seems to have one. Thanks
for the reply.

if(!ref_listCtrl)
    return FALSE;

BOOL CMyListView::GetSysImgList()
{
SHFILEINFO shFinfo;
HIMAGELIST hImgList = NULL;

CListCtrl& m_listCtrl = GetListCtrl( );


m_ is generally only used for member variables, it is confusing when you
give m_ names to stack variables.


I learn fairly quickly and I am certain that I won't make the same
mistake. Thanks for the reply.

if ( m_listCtrl.GetImageList( TVSIL_NORMAL ) )
m_imgList.Detach();


why are you detaching whats in your m_imgList? Should you destroy it if
you
don't want to use it anymore?


The reason that I am detaching the image list is so that I can ensure
that the image list contains only the built in system list and not any
other list that may have been used somewhere in the code elsewhere. If
you mean "detach" of this list then I believe that I have in the
destructor of my derieved ListView class. Thanks for the reply.

hImgList = (HIMAGELIST)SHGetFileInfo( _T("C:\\"), 0, &shFinfo, sizeof
( SHFILEINFO ), SHGFI_SYSICONINDEX | SHGFI_SMALLICON);

if ( !hImgList )
{
m_strError = "Cannot retrieve the Handle of SystemImageList!";
return FALSE;
}

if ( !m_imgList.Attach( hImgList ) )
{
m_strError = "Cannot Attach SystemImageList-Handle";
return FALSE;
}

m_listCtrl.SetImageList( &m_imgList, LVSIL_SMALL );
return TRUE; // OK
}


AliR.- Hide quoted text -

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