[PyQt] QSqlTableModel.beforeInsert signal (new style signal/slot)

[Phil Thompson]

On Fri, 3 Dec 2010 17:19:00 +0100, "KONTRA, Gergely" <pihentagy at gmail.com>
wrote:
> On Fri, Dec 3, 2010 at 16:06, Phil Thompson
> <phil at riverbankcomputing.com>wrote:
> 
>> On Fri, 3 Dec 2010 15:46:55 +0100, "KONTRA, Gergely"
>> <pihentagy at gmail.com>
>> wrote:
>> > Hi!
>> >
>> > I am trying to connect the beforeInsert signal of a QSqlTableModel,
>> > and having some problems.
>> >
>> > I've found this similar thread:
>> > http://www.mail-archive.com/pyqt@riverbankcomputing.com/msg20117.html
>> >
>> > However, I am using pyqt with py3k, so I prefer the new style signal
>> > and slots, but I appreciate any working solution...
>> >
>> > So my attempt based on the thread:
>> > class BatteryMain(base_class, form_class):
>> >        # ...
>> >        def cycle_started(self, record):
>> >                print("Inserting {!r}".format(record))
>> >
>> >        def battery_load(self, filename):
>> >                self.cycles_model = QSqlTableModel(db=self.battery_db)
>> >                self.connect(self.cycles_model,
>> > SIGNAL("beforeInsert(QSqlRecord
>> > &)"), self.cycle_started)
>> >
>> > RESULT:
>> > QObject::connect: Cannot queue arguments of type 'QSqlRecord&'
>> > (Make sure 'QSqlRecord&' is registered using qRegisterMetaType().)
>> >
>> > Another attempt with new style signals and slots:
>> >
>> > class BatteryMain(base_class, form_class):
>> >        # ...
>> >        @pyqtSlot('QSqlRecord &')
>> >        def cycle_started(self, record):
>> >                print("Inserting {!r}".format(record))
>> >
>> >        def battery_load(self, filename):
>> >                self.cycles_model = QSqlTableModel(db=self.battery_db)
>> >
>> self.cycles_model.beforeInsert.connect(self.cycle_started)
>> >
>> > RESULT:
>> >  File "D:\prg\biQazo\biQazo.py", line 145, in battery_load
>> >    self.cycles_model.beforeInsert.connect(self.cycle_started)
>> > TypeError: connect() failed between beforeInsert(QSqlRecord) and
>> unislot()
>> >
>> > Could anybody tell me the correct syntax, please?
>>
>> It's not a syntax problem.
>>
>> Are you using threads?
>>
> 
> Yes, I am using threads. Is it valid to insert into a QSqlTableModel a
new
> row in a QThread?
> I have a worker thread, which collects data, and inserts it into the
> QSqlTableModel, and I'd like to get notified with this beforeInsert
signal
> in the GUI thread.
> 
>>
>> I would guess that you can't use signals that take a QSqlRecord across
>> threads, probably because they are not passed as const (to allow them
to
>> be
>> updated by a connected slot).
>>
> That sounds sad. I thought this signal will make it easy to communicate
> between threads.
> Then what is the solution to communicate between the worker thread, and
the
> main GUI thread? Cutsom signal?

Yes, or a custom event (which is how cross-thread signals are handled
anyway).

Phil