Qt-interest Archive, April 2007
Error in function call QObject::property(name) (Qt4.3.0beta)
Message 1 in thread
Hi,
I created an QAxObject base on IDispatch *
Then, I made a function call:
QString html = iObject.generateDocumentation();
where the html was generated correctly.
From the html I found a property: "int myInt", which was originated
from an QAxBindable class:
Q_PROPERTY( int myInt READ myInt WRITE setMyInt )
Clicking on the property I got help:
“Read this property's value using QObject::property:
int val =object->property("myInt").toInt();
“
I did it like:
int val = iObject.property("myInt").toInt();
// int val = iObject.myInt(); // same above
but I got error:
ASERT "id < 0" in file .\qaxbase.cpp, line 3642
I got stuck in how to retrieve an OLE object.
Is this a bug in QObject or a bug in the QAxObject base on
IDispatch(machine generated by dumpcpp tool)?
Thanks,
Lingfa
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Message 2 in thread
"Lingfa Yang" <lingfa@xxxxxxx> wrote in message
news:4624F3FA.9060800@xxxxxxxxxx
> Hi,
>
> I created an QAxObject base on IDispatch *
> Then, I made a function call:
> QString html = iObject.generateDocumentation();
> where the html was generated correctly.
>
> From the html I found a property: "int myInt", which was originated from
> an QAxBindable class:
> Q_PROPERTY( int myInt READ myInt WRITE setMyInt )
What does the QAxBindable class do here? QAxBindable is usually used in
QAxServer, whereas QAxObject is used in QAxContainer.
> Clicking on the property I got help:
> ?Read this property's value using QObject::property:
> int val =object->property("myInt").toInt();
> ?
>
> I did it like:
> int val = iObject.property("myInt").toInt();
> // int val = iObject.myInt(); // same above
> but I got error:
> ASERT "id < 0" in file .\qaxbase.cpp, line 3642
>
> I got stuck in how to retrieve an OLE object.
> Is this a bug in QObject or a bug in the QAxObject base on
> IDispatch(machine generated by dumpcpp tool)?
Did this work with 4.2.x?
Does the object the IDispatch* you get back refers to have a property
"myInt" (according to the type library)?
Volker
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Message 3 in thread
Volker Hilsheimer wrote:
>"Lingfa Yang" <lingfa@xxxxxxx> wrote in message
>news:4624F3FA.9060800@xxxxxxxxxx
>
>
>>Hi,
>>
>>I created an QAxObject base on IDispatch *
>>Then, I made a function call:
>>QString html = iObject.generateDocumentation();
>>where the html was generated correctly.
>>
>>From the html I found a property: "int myInt", which was originated from
>>an QAxBindable class:
>>Q_PROPERTY( int myInt READ myInt WRITE setMyInt )
>>
>>
>
>
>What does the QAxBindable class do here? QAxBindable is usually used in
>QAxServer, whereas QAxObject is used in QAxContainer.
>
>
You're right. Here, in container, nothing to do with QAxBindable class.
What I just mentioned, or made sure, there were a property NAME "myInt",
a READ function "myInt" , and a WRITE func "setMyInt" when I generated
the ActiveQt control.
>>Clicking on the property I got help:
>>“Read this property's value using QObject::property:
>>int val =object->property("myInt").toInt();
>>“
>>
>>I did it like:
>>int val = iObject.property("myInt").toInt();
>>// int val = iObject.myInt(); // same above
>>but I got error:
>>ASERT "id < 0" in file .\qaxbase.cpp, line 3642
>>
>>I got stuck in how to retrieve an OLE object.
>>Is this a bug in QObject or a bug in the QAxObject base on
>>IDispatch(machine generated by dumpcpp tool)?
>>
>>
>
>
>Did this work with 4.2.x?
>
>
Not 4.2.x, but I did test in 4.1.1, which failed either --- that's why I
downloaded the newest version of Qt.
>Does the object the IDispatch* you get back refers to have a property
>"myInt" (according to the type library)?
>
>
>
Yes, it is in the type library.
Thanks,
>Volker
>
>
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[ signature omitted ]
Message 4 in thread
>>>Hi,
>>>
>>>I created an QAxObject base on IDispatch *
>>>Then, I made a function call:
>>>QString html = iObject.generateDocumentation();
>>>where the html was generated correctly.
>>>
>>>From the html I found a property: "int myInt", which was originated
>>>from an QAxBindable class:
>>>Q_PROPERTY( int myInt READ myInt WRITE setMyInt )
>>>
>>
>>
>>What does the QAxBindable class do here? QAxBindable is usually used in
>>QAxServer, whereas QAxObject is used in QAxContainer.
>>
> You're right. Here, in container, nothing to do with QAxBindable class.
> What I just mentioned, or made sure, there were a property NAME "myInt",
> a READ function "myInt" , and a WRITE func "setMyInt" when I generated
> the ActiveQt control.
So, you have an ActiveQt based control (i.e. a QWidget that you have
exposed as an ActiveX control), and you use that ActiveX control in your
Qt application via QAxObject/QAxWidget?
Why? Just use the QWidget directly.
Volker
--
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Message 5 in thread
>So, you have an ActiveQt based control (i.e. a QWidget that you have
>exposed as an ActiveX control), and you use that ActiveX control in your
>Qt application via QAxObject/QAxWidget?
>
>Why? Just use the QWidget directly.
>
>
>Volker
>
>
Very good question!
That is the need from automating PowerPoint.
We need to insert these controls to PowerPoint and pass to our clients
for better presentation.
For example, a plotter holds xy-data. We insert the plotter control and
persistent data to PowerPoint, so that customer can zoom in/out/shift
during the slider show, which is much better than just insert several
frames of STATIC plot images.
What we are doing is after adding the control:
shape = shapes->AddOLEObject(100, 100, 512, 320, className, false);
how to handle(initialize/customize) the object.
I can get IDispatch, and make a handler.
IDispatch *idispatch = shape->OLEFormat->Object();
qwtwrapperaxLib::IQwtSimplePlotAx iObject(idispatch);
but this iObject somehow does not works well.
Any further suggestions are appreciated.
Lingfa
--
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Message 6 in thread
"Lingfa Yang" <lingfa@xxxxxxx> wrote in message
news:46250286.9060107@xxxxxxxxxx
>
>>So, you have an ActiveQt based control (i.e. a QWidget that you have
>>exposed as an ActiveX control), and you use that ActiveX control in your
>>Qt application via QAxObject/QAxWidget?
>>
>>Why? Just use the QWidget directly.
>>
>>
>>Volker
>>
> Very good question!
> That is the need from automating PowerPoint.
> We need to insert these controls to PowerPoint and pass to our clients
> for better presentation.
Ok, that explains why you make your QWidget into an ActiveX. But why do
you use that widget not directly in your Qt code? Anyway...
> For example, a plotter holds xy-data. We insert the plotter control and
> persistent data to PowerPoint, so that customer can zoom in/out/shift
> during the slider show, which is much better than just insert several
> frames of STATIC plot images.
>
> What we are doing is after adding the control:
> shape = shapes->AddOLEObject(100, 100, 512, 320, className, false);
> how to handle(initialize/customize) the object.
> I can get IDispatch, and make a handler.
> IDispatch *idispatch = shape->OLEFormat->Object();
> qwtwrapperaxLib::IQwtSimplePlotAx iObject(idispatch);
> but this iObject somehow does not works well.
>
> Any further suggestions are appreciated.
Are you sure that the IDispatch returned references a
qwtwrapperaxLib::IQwtSimplePlotAx?
Volker
--
[ signature omitted ]
Message 7 in thread
>Ok, that explains why you make your QWidget into an ActiveX. But why do
>you use that widget not directly in your Qt code? Anyway...
>
>
>
If the ActiveX does not take user’s date, adding the control to ppt is
enough, then, the user can load the data during the slide-show --- but
this is not good. The good approach is save both the data and the
control to ppt, so that the user needn’t loading.
>
>Are you sure that the IDispatch returned references a
>qwtwrapperaxLib::IQwtSimplePlotAx?
>
>
It does not return the reference to IQwtSimplePlotAx, instead, the class
takes IDispatch in its constructor to create a handler.
dumpcpp generates two classes, one with “I”, the other without.
class QWTWRAPPERAXLIB_EXPORT IQwtSimplePlotAx : public QAxObject
class QWTWRAPPERAXLIB_EXPORT QwtSimplePlotAx : public QAxWidget
The first one takes IDispatch in its contructor:
IQwtSimplePlotAx(IDispatch *subobject = 0, QAxObject *parent = 0)
: QAxObject((IUnknown*)subobject, parent)
{
internalRelease();
}
The second one takes iface;
QwtSimplePlotAx(IQwtSimplePlotAx *iface)
: QAxWidget()
{
initializeFrom(iface);
delete iface;
}
or default constuctor:
QwtSimplePlotAx(QWidget *parent = 0, Qt::WindowFlags f = 0)
: QAxWidget(parent, f)
{
setControl("{52ac57f1-f548-4012-aaa3-5d589a02c8f3}");
}
The default one, itself, works well. (I am 100% sure about its property
calls or direct function calls.)
Our company has Qt license support, so should I dig that path, or stay
with this board?
Thanks,
Lingfa
--
[ signature omitted ]
Message 8 in thread
"Lingfa Yang" <lingfa@xxxxxxx> wrote in message
news:462633C7.1020605@xxxxxxxxxx
>
>>Ok, that explains why you make your QWidget into an ActiveX. But why do
>>you use that widget not directly in your Qt code? Anyway...
>>
>>
> If the ActiveX does not take user?s date, adding the control to ppt is
> enough, then, the user can load the data during the slide-show --- but
> this is not good. The good approach is save both the data and the
> control to ppt, so that the user needn?t loading.
>
>>
>>Are you sure that the IDispatch returned references a
>>qwtwrapperaxLib::IQwtSimplePlotAx?
>>
>
> It does not return the reference to IQwtSimplePlotAx, instead, the class
> takes IDispatch in its constructor to create a handler.
Exactly. If the IDispatch* returned is not implemented by a
QwtSimplePlotAx object, then everything will go wrong. You must be sure
that the IDispatch* returned is the one implemented by an object of the
type that you want to create.
It's like connecting to a slot in an object that doesn't have such a slot.
You can still do it, but it won't work.
> dumpcpp generates two classes, one with ?I?, the other without.
> class QWTWRAPPERAXLIB_EXPORT IQwtSimplePlotAx : public QAxObject
> class QWTWRAPPERAXLIB_EXPORT QwtSimplePlotAx : public QAxWidget
> The first one takes IDispatch in its contructor:
> IQwtSimplePlotAx(IDispatch *subobject = 0, QAxObject *parent = 0)
> : QAxObject((IUnknown*)subobject, parent)
> {
> internalRelease();
> }
> The second one takes iface;
> QwtSimplePlotAx(IQwtSimplePlotAx *iface)
> : QAxWidget()
> {
> initializeFrom(iface);
> delete iface;
> }
> or default constuctor:
> QwtSimplePlotAx(QWidget *parent = 0, Qt::WindowFlags f = 0)
> : QAxWidget(parent, f)
> {
> setControl("{52ac57f1-f548-4012-aaa3-5d589a02c8f3}");
> }
> The default one, itself, works well. (I am 100% sure about its property
> calls or direct function calls.)
>
> Our company has Qt license support, so should I dig that path, or stay
> with this board?
You can go through support, but guess who will answer your ActiveQt
question :)
Volker
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Message 9 in thread
>Exactly. If the IDispatch* returned is not implemented by a
>QwtSimplePlotAx object, then everything will go wrong.
>
>
Thank you so much.
This is a key point --- very close to problem solved I guess.
First, I do not explicitly implement any return which brings IDispatch*.
My augment is that IDispatch is obtained from
PowerPoint::OLEFormat::Object(), which is machine-generated code.
inline IDispatch* OLEFormat::Object() const
{
QVariant qax_result = property("Object");
if (!qax_result.constData()) return 0;
Q_ASSERT(qax_result.isValid());
return *(IDispatch**)qax_result.constData();
}
From above, why I have to implement an IDispatch* return in my coding?
Second, I tried to find a how-to-do Qt example about the IDispatch*
return. Not found in examples\ActiveQt!
Would you please tell me how to implement?
I appreciate your crucial help.
Lingfa
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Message 10 in thread
Lingfa Yang wrote:
>
>> Exactly. If the IDispatch* returned is not implemented by a
>> QwtSimplePlotAx object, then everything will go wrong.
>>
> My augment is that IDispatch is obtained from
> PowerPoint::OLEFormat::Object(), which is machine-generated code.
>
One more progress is I took the same control and inserted to ppt by MFC:
OLEFormat oOLEFmt = oShape.GetOLEFormat();
IQwtSimplePlotAx oSimplePlot = oOLEFmt.GetObject();
// manapulate the interface object
long myInt = oSimplePlot.GetMyInt(); // right
oSimplePlot.SetMyInt(myInt+10); // right
long newValue = oSimplePlot.GetMyInt(); // excellent
Everything works well --- I mean by MFC the same (IDispatch *) was
returned, and an interface object was obtained in the same manner, and
one can feel free to manapulate programmatically. --- which means there
is nothing wrong about my ActiveX control. So what's wrong with my Qt
automating ppt?
Thanks,
Lingfa
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