Question

In my main window (QMainWindow) I have a QTableView (named commandsTableView). Now I want to react on its selection changes.

I made a slot and connected it manually to ui.commandsTableView->selectionModel(). All works fine.

But then I thought: why not use auto-connection (especially that there will be more connections to be done)? At least it will add more force to consistent naming rules.

Yet I wasn’t able to find proper name syntax. I tried:

• on_commandsTableView_selectionModel_selectionChanged,
• on_commandsTableViewSelectionModel_selectionChanged,
• on_commandsTableView_selectionChanged,
• on_commandsTableView___selectionChanged

but neither worked. In all cases there is there is a message on output when running the app (with corresponding slot name, here only first given as an example):

QMetaObject::connectSlotsByName: No matching signal for on_commandsTableView_selectionModel_selectionChanged(QItemSelection,QItemSelection)

(Why there are no assertions in response for connection errors – that I cannot understand. I lost much time wondering what is wrong before I spotted those – and alike – messages on output.)

The object returned by ui.commandsTableView->selectionModel() has an empty name. But setting it to selectionModel prior to making a call to connectSlotsByName doesn’t help either.

Answer 1

According to the documentation connectSlotsByName() only supports signatures like


void on_<object name>_<signal name>(<signal parameters>);


According to the sources that’s the only form it checks (watch how it collects a list of children, then matches parent’s method names against names of the children).

Hence, to be able to use auto-connection you would have needed a named selection model, which would continue existing from the call to connectSlotsByName() onwards. Each time you change the selection model (not likely) or the model (likely) you’d have to name the selection model and auto-connect again. But alas connectSlotsByName() will duplicate all other connections as it doesn’t seem to check if connections are unique, so we have to connect signals to such dynamic children as models, scenes etc manually.