Qt connect QAction to function with arguments

Question

In my Qt 5.6 program I need to connect QMenu Click (QAction) to function and provide some arguments. I can connect to function without arguments and it is working:

connect(MyAction, &QAction::triggered, function);

But, when I'm trying to add some arguments:

connect(MyAction, &QAction::triggered, function(arguments));

I'm getting an error:

C2664: "QMetaObject::Connection QObject::connect(const QObject *,const char *,const char ,Qt::ConnectionType) const": can't convery arg 2 from "void (__thiscall QAction:: )(bool)" to "const char *"

My example function:

void fuction(char x, char y, int z);

Thank you for any advice.

LogicStuff · Accepted Answer · 2018-08-13T22:17:09.793

11

function(arguments) is a function call, you want to bind the function to the arguments and create new callable object instead, using std::bind:

connect(MyAction, &QAction::triggered, std::bind(function, arguments));

or you can use a lambda function:

connect(MyAction, &QAction::triggered, [this]()
{
    function(arguments);
});

edited Aug 13 '18 at 22:17

answered Apr 19 '16 at 17:49

LogicStuff

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@LogicStuff what do you mean by "you want to bind the arguments to the function" ? – AAEM Aug 13 '18 at 22:11
@Ahmed Is the terminology OK now? – LogicStuff Aug 13 '18 at 22:18
@LogicStuff yes it is OK – AAEM Aug 13 '18 at 22:19
@LogicStuff but i have a problem with understanding the lambda function – AAEM Aug 13 '18 at 22:21
1

this is MUCH better and easier to understand than the SLOTS garbage. – LUser Jul 31 '20 at 20:58

score 4 · Answer 2 · answered Apr 19 '16 at 17:48

4

You want to use std::bind as in:

connect(MyAction, &QAction::triggered, std::bind(&function, x, y, z));

answered Apr 19 '16 at 17:48

Super-intelligent Shade

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Qt connect QAction to function with arguments

2 Answers2