how to connect an openfile signal to a widget slot?

[fatecasino]

@stampede: it worked like a charm!!
thank you very much..I always really confused with the usage of "this"
What is the actual difference between the two lines??

this->mainPlot->plotMainCurve(file);

this->mainPlot->plotMainCurve(file);

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widget->mainPlot->plotMainCurve(fileName);

widget->mainPlot->plotMainCurve(fileName);

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[FelixB]

"this" is a pointer to the object which "posesses" the current method.

the difference is that the second line "widget->mainPlot..." works only if "mainPlot" is public. That's why I recommended to create a getter. The following would have worked too:

widget->Get2DPlot()->plotMainCurve(file)

widget->Get2DPlot()->plotMainCurve(file)

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[stampede]

What is the actual difference between the two lines??

You use "this" keyword from class methods when you refer to actualy used class instance ( the object that "calls" the method or access the class member ).
Of course you have access to all members of the class in this case.

Here

widget->mainPlot->plotMainCurve(fileName);

you use some object "widget" to call the method. You can access only public members of the "widget" object ( unless you are a friend of a class )

This basic knowledge is mandatory in C++ programming, I really recommend some reading before going into qt programming ( you can find some useful info here: http://www.qtcentre.org/threads/29-W...ourite-C-books )