A signal problem

[qcoderpro]

Hi,

I have a QComboBox named cboBox, void itemChanged(int); slot and a connection like this:

connect(cboBox, SIGNAL(currentItemChanged(int)), this, SLOT(itemChanged(int)));
...
void DialogTest::itemChanged(int item)
{
  ...
}

But I get this error: QObject::connect: No such signal QComboBox::currentItemChanged(int)

[CP71]

@qcoderpro
Hi,
"But I get this error: QObject::connect: No such signal QComboBox::currentItemChanged(int)" means currentItemChanged isn't a signal.

Maybe you want to write currentIndexChanged(int index).

[qcoderpro]

@CP71

Thank you. And if I want to use the new style, I need lambda, right?
I declared it this way but doesn't work:

connect(cboBox, &QComboBox::currentIndexChanged, this, [this](int item) {
        itemChanged(item);
    });

[Pl45m4]

@qcoderpro said in A signal problem:

And if I want to use the new style, I need lambda, right?

Lambdas are a different thing...
You can achieve the same result by connecting your button to your slot like this:

connect(cboBox, &QComboBox::currentIndexChanged, this, &DailogTest::itemChanged);

[qcoderpro]

@Pl45m4

It doesn't work because the slot has two different versions, one int and another a string.

Error: no matching function

[Pl45m4]

@qcoderpro

https://doc.qt.io/qt-5/qcombobox.html#currentIndexChanged

[Christian Ehrlicher]

You're looking for qOverload() I guess

[qcoderpro]

I use the old syntax. Thanks.