QAxObject, how work with IDispatch?

marceloarguello700

I have a dll with Com object, I can instantiate the object and work with it but have a problem with a collection.

Reading the .generateDocumentation() of QAxObject, see that one method of com dll give me IDispatch pointer:

IDispatch * val = object->property("Systems").toIDispatch*();
When work with the same object in Visual Basic,
the method retrieve a collection of item "System"
And the class "System" is defined in the DLL.

In Visual Basic do:
Dim system As DataSystemFilelib.System
Set system = obj.systems().items(1)

I need to load one item of the collection:
How declare the "System" class in QT
Also when compile give:
error: 'class QVariant' has no member named 'toIDispatch'
So,How can work wit this.

SGaist

Hi,

Shouldn't it rather be:

IDispatch * val = object->property("Systems").value<IDispatch*>();

?

marceloarguello700

Thanks for the reply, Now compile ok,
the next is how work with the Idispach,
The property give me a Collection of System class, I need to retrieve Items, work with their,
also the items have properties with another Collections.
how i declare the system class?
Dim system As DataSystemFilelib.System
Set system = obj.systems().items(1)
Greetings

SGaist

Are you sure that you should use IDispatch ? What's the original class you want to access ?

Chris Kawa

If an interface returns IDispatch* then you can create a child QAxObject from it using querySubObject.
So instead of

IDispatch * val = object->property("Systems").value<IDispatch*>();

you can do

QAxObject* val = object->querySubObject("Systems");

You can then generateDocumentation on that object to see what kind of access it provides (usually something like Item(int index)) to access its contents.

marceloarguello700

Thanks for the reply
SGaist:
I dont want to work with IDispatch because is treacky complicated.
Just want to transform one old Visual Basic 6 source to my new qt app.
The original class is defined in the dll like: DataSystemFilelib.System
then i do: Dim system
As DataSystemFilelib.System
and get the first item:
Set system = obj.systems().items(1)

Chris Kawa:
Your answer is not clear to me,
In the last code lines your assign twice time the val?
how be the correct way?
can provide a sample to retrieve the firt item, or the count items?
The documentation only provide way to work with numbers or string but dont
provide sample of how do this.
Greetings

Chris Kawa

In the last code lines your assign twice time the val?

What? You should read the text between the code :) I said that you can do the second line instead of the first one. Not both of them.
QAxObject wraps around IDispatch. As I said, you can call generateDocumentation on the QAxObject to get a documentation of what interface the object provides and code snippets of how to access them.
I don't know the exact interface of these types so I can only guess, and it probably goes something like this (don't expect to work if you just copy/paste it):

QAxObject obj("Whatever.the.obj.is.in.your.example");
QAxObject* systems = ob.querySubObject("Systems");
int numberOfItems = systems->property("Count").toInt();
if(numberOfItems > 0)  {
    QAxObject* firstSystem = systems->querySubObject("Item(int)", 1);
    //do something with firstSystem
}

marceloarguello700

Chris Kawa:
Thank, Now it work, sorry for the misunderstanding "So instead of:"
i get in this trouble because i read the generatedDocumentation()
´IDispatch * val = object->property("Systems").toIDispatch*();´

Lack of knowledge and lack of samples.
Greetings