How to pass paramaters to "addAction"

Anonymous_Banned275

I am lost again in C++.
My function is declared as such :
Run_TAB (int )
and I am getting this error

/media/qe/TSET_QT_LABEL/QT_PROGRAMS/JUNE 4 WORKCOPY 1/CAT/mdi/mainwindow.cpp:682: error: lvalue required as unary ‘&’ operand
../../../JUNE 4 WORKCOPY 1/CAT/mdi/mainwindow.cpp: In member function ‘void MainWindow::createActions()’:
../../../JUNE 4 WORKCOPY 1/CAT/mdi/mainwindow.cpp:682:69: error: lvalue required as unary ‘&’ operand
682 | this, &MainWindow::Run_TAB(selection));
| ~~~~~~~~~^

And it looks as Run_TAB is passed to addAction as
QKey Sequence.
I do not get that at all .

It woks fine when Run_TAB is declared as (void) - no parameters.

template<typename Functor>
QAction *addAction(const QString &text, Functor functor, const QKeySequence &shortcut = 0);
template<typename Functor>
QAction *addAction(const QString &text, const QObject *context, Functor functor, const QKeySequence &shortcut = 0);
template<typename Functor>
QAction *addAction(const QIcon &icon, const QString &text, Functor functor, const QKeySequence &shortcut = 0);
template<typename Functor>
QAction *addAction(const QIcon &icon, const QString &text, const QObject *context, Functor functor, const QKeySequence &shortcut = 0);
#else

Here is my implementation which gives the error.

QAction *CAT_TAB = CATMenu->addAction(tr("&Bluetoooth  Development (TAB) "),
                                      this, &MainWindow::Run_TAB(selection));

sierdzio

@AnneRanch said in How to pass paramaters to "addAction":

&MainWindow::Run_TAB(selection)

This is a "pointer to function", similar to what you will find in modern connect statement:

connect(this, &Object::foo,
    that, &Object::bar)

This only tells the function what function to call on which object. But it does not tell it what parameters to pass.

And so the same rules apply: you cannot pass parameters in this call - it should be:

QAction *CAT_TAB = CATMenu->addAction(tr("&Bluetoooth  Development (TAB) "),
                                      this, &MainWindow::Run_TAB);

If you need to pass some concrete data, you can use a lambda:

QAction *CAT_TAB = CATMenu->addAction(tr("&Bluetoooth  Development (TAB) "),
                                      this, [=]() {
    this->Run_TAB(selection);
});

VRonin

std::bind also works:

QAction *CAT_TAB = CATMenu->addAction(tr("&Bluetoooth  Development (TAB) "),
                                      this, std::bind(&MainWindow::Run_TAB,this,selection));