Qt5 new signals-slots syntax does not work [SOLVED]

lgeyer

Are you sure you are using Qt5 (and not Qt4)?

anaksimandr

yes. at other place this method works

cincirin

Note that QComboBox::currentIndexChanged has two signals. Compiler don't know what signal do you want. Need to explicitly tell the compiler correct functions address.

edit: for example for signal with QString argument, you need something like this:
@
void (QComboBox:: *indexChangedSignal)(QString) = &QComboBox::currentIndexChanged;
connect(comboBox, indexChangedSignal, this, &MyClass::func1)
@

anaksimandr

when i tried to compile code above i have this
error: C2440: 'initializing' : cannot convert from 'overloaded-function' to 'void (__thiscall QComboBox::* )(QString)'
None of the functions with this name in scope match the target type

anaksimandr

@connect(cmbProfiles, SIGNAL(currentIndexChanged(const QString&)),
this, SLOT(loadProfilesDetails(const QString&)));@
And now I see that in qt5 this code does not work too, it compiles but does not work. Sorry for my inattention.

anaksimandr

So now I must ask how to connect func to signal QComboBox::currentIndexChanged(const QString & text) in Qt5 ?

lgeyer

As cincirin already mentioned you will have to explicitly cast overloaded signals when using the function pointer syntax.

connect(cmbProfiles,
        static_cast<void (QComboBox::*)(const QString &)>(&QComboBox::currentIndexChanged), 
        this,
        &MyClass::loadProfilesDetails);

The equivalent of the string-based syntax is

connect(cmbProfiles, 
        SIGNAL(currentIndexChanged(const QString &)),
        this,
        SLOT(loadProfilesDetails(const QString &)));

or

connect(cmbProfiles, 
        SIGNAL(currentIndexChanged(QString)),
        this,
        SLOT(loadProfilesDetails(QString)));

anaksimandr

It works, thanks to all.

Ph0t0n

Wow... it works, but that is really ugly!

j-hap

I know this is quite old, but if someone ends up here again, this is the up-to-date way of defining an overload when connecting an overloaded signal: QOverload<int>::of(&QComboBox::currentIndexChanged)