How to connect to a slot with multiple arguments

hobbyProgrammer

Hi,

I have a slot that I'd like to connect to. The slot contains 2 arguments.

void mySlot(int, int);

I already connected a slot with one argument like this:

    QSignalMapper *signalMapper = new QSignalMapper(this);
    connect(act, SIGNAL(triggered()), signalMapper, SLOT(map()));
    signalMapper->setMapping(act, ID);
    connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(goToSlot(int)));

but now I would like to connect SLOT(mySlot(int, int))

Is there anyone who knows how to do this?
Thanks in advanced.

Christian Ehrlicher

@hobbyProgrammer said in How to connect to a slot with multiple arguments:

Is there anyone who knows how to do this?

And what should the second parameter be?
Using the old signal/slot syntax you can set the second parameter as a default parameter. Using the new signal/slot syntax you can use a lambda.

hobbyProgrammer

@Christian-Ehrlicher Hi,
the first and second arguments are integers.

mySlot(int, int);

Christian Ehrlicher

@hobbyProgrammer said in How to connect to a slot with multiple arguments:

the first and second arguments are integers.

I did not ask for the data type, I ask what value you want to pass... and I already gave you the answer on how to achieve it.

hobbyProgrammer

@Christian-Ehrlicher oh alright. The first argument is an ID that is the result of a QSqlQuery. The second argument is a simple 1, 2 or 3 (depends on which signal is triggered).

hobbyProgrammer

@Christian-Ehrlicher said in How to connect to a slot with multiple arguments:

Using the old signal/slot syntax you can set the second parameter as a default parameter.

I am using the old signal/slot syntax. But how do I set the second parameter as a default parameter?
Do you have example code?

Christian Ehrlicher

@hobbyProgrammer said in How to connect to a slot with multiple arguments:

Do you have example code?

Really C++ basics: https://en.cppreference.com/w/cpp/language/default_arguments

hobbyProgrammer

@Christian-Ehrlicher

MainWindow.h:

private slots:
    void setStatus(int, int);

MainWindow.cpp:

void MainWindow::connectActions()
{
        connect(value, SIGNAL(statusSafe()), signalMapper, SLOT(map()));
        signalMapper->setMapping(values, ID);
        connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(setStatus(int, 1)));
}

void MainWindow::setStatus(int id, int status)
{
//some code
}

this combination still gives me this error:

QObject::connect: No such slot MainWindow::setStatus(int, 1) in ..\..\..\Documents\QtProject\mainwindow.cpp:67
QObject::connect:  (receiver name: 'MainWindow')

Christian Ehrlicher

@hobbyProgrammer Is it so hard reading the links I gave you?

hobbyProgrammer

@Christian-Ehrlicher yes I don't really seem to understand it.

is this what you meant by setting the default parameter?

void MainWindow::setStatus(int id, int status = 1)
{
//some code
}

because that won't help me at all. I need the status to be variable. But different statusses have different signals so I thought that this might do the trick, but it didn't.

void MainWindow::connectActions()
{
        connect(value, SIGNAL(statusSafe()), signalMapper, SLOT(map()));
        signalMapper->setMapping(values, ID);
        connect(signalMapper, SIGNAL(mapped(int)), this, SLOT(setStatus(int, 1)));
}

Christian Ehrlicher

As I already told you:

Using the new signal/slot syntax you can use a lambda.

C++ basics (again)

KroMignon

@hobbyProgrammer said in How to connect to a slot with multiple arguments:

void MainWindow::setStatus(int id, int status = 1)
{
//some code
}

As @Christian-Ehrlicher told you, this is a C++ basic knowledge; I think you should start to learn C++ basics this will help you to avoid basic errors.

Default values for arguments are declared in the class declaration:

private slots:
    void setStatus(int id , int status = 0);

SGaist

Hi,

Where do you get that ID ?

You'll click on the action, get the ID and then call the slot ?