[Qt-interest] No RTTI information for QTreeWidgetItem

[Scott Aron Bloom]

One solution that might help you... and in fact, you cant do it with the
role...

 

Simply overload all the constructors, to take in your enumeration, so
any derived class will clearly have to use one of your types.


Scott

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Eric Clark
Sent: Tuesday, June 02, 2009 9:53 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

I know what you mean. I have done that with derived classes before, that
is probably a good idea to fix my concern. Well... as long as everyone
follows the rules. J I work on a framework, like Qt, but it is a 3D
modeling and simulation framework. Sometimes I get concerned with
developers using our framework not following the rules. But, that is
their problem, right.

 

Thank you for all your help, I really do appreciate it Scott!

 

Eric

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Scott Aron Bloom
Sent: Tuesday, June 02, 2009 11:44 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

Gotcha...  I don't think its any different then with custom model roles.

 

In my derived class, I usually create a public enum and create a new
"add to this number and you are safe" enumeration


Scott

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Eric Clark
Sent: Tuesday, June 02, 2009 9:39 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

No. I do not mind doing this, actually it is probably faster than a
dynamic cast, but I am a little concerned that there is no way to
"reserve" the type number like there is with custom Event types. With
Events, you can register your event number, but I do not see the ability
to do this with QTreeWidgetItem's types. Is there a way that you know
of? I am just concerned about the same number being reused with someone
else's derived type.

 

Eric

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Scott Aron Bloom
Sent: Tuesday, June 02, 2009 11:28 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

Its really no different.. is it any different doing 5-10 (depending on
how many QTreeWidgetItem derived classes) if ( item->type() ) vs 5-10
castes?

Scott

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Eric Clark
Sent: Tuesday, June 02, 2009 6:47 AM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

I had a feeling that was the only solution. Thank you very much!

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Scott Aron Bloom
Sent: Monday, June 01, 2009 5:27 PM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

No it wont.. I missed that...  

 

Instead do the following, make sure you set your Type during the
construction, and call QTreeWidgetItem::type() to figure out what type
of type it is

 

Scott

 

 

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Eric Clark
Sent: Monday, June 01, 2009 2:08 PM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] No RTTI information for QTreeWidgetItem

 

Scott,

 

Thank you for the response, but I would not have a problem using
qobject_cast, except that QTreeWidgetItem does not inherit QObject. Will
qobject_cast work on non-QObjects?

 

Eric

 

From: Scott Aron Bloom [mailto:Scott.Bloom at sabgroup.com] 
Sent: Monday, June 01, 2009 4:04 PM
To: Eric Clark; qt-interest at trolltech.com
Subject: RE: [Qt-interest] No RTTI information for QTreeWidgetItem

 

Don't use RTTI on QT based objects... (in fact its rather unsafe when
crossing any DLL boundry on windows...) use qobject_cast

 

Scott

 

From: qt-interest-bounces at trolltech.com
[mailto:qt-interest-bounces at trolltech.com] On Behalf Of Eric Clark
Sent: Monday, June 01, 2009 1:05 PM
To: qt-interest at trolltech.com
Subject: [Qt-interest] No RTTI information for QTreeWidgetItem

 

Hello All,

 

I have a class that inherits QTreeWidgetItem. When I attempt to do a
dynamic_cast on a QTreeWidgetItem that was created using my subclass
BaseTreeWidgetItem I get an exception thrown by Microsoft C++ that says
the object is a __non_rtti_object. Has anyone seen this problem? If I
just cast the object instead of using a dynamic_cast everything works
just fine.

 

Thanks in advance!

Eric

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