[Qt-interest] How associate slot sender with my data object?

[John McClurkin]

Ed Sutton wrote:
> I am getting started using signals and slots. I use QSignalMapper with QGroupBox collection of QRadioButtons that select video channels.  
> 
> In the received slot, how can I both retrieve the sender's checked state and associate the sender with it's related channel data object?  Do QT widgets support a pointer to a void* "tag object"?  Some way to associate my data object with the signal sender?  I tried to make my own but cannot seem to derive from QRadioButton.
> 
> In order to determine the QRadioButton checked state in the slot, the best choice seems to use the SLOT(channelChanged(QWidget*)) signature.  In order to associate the sender with my data object, must I make my own associative map collection?  Is this typical or is there a better approach?
> 
> Thanks in advance for sharing your experience,
> 
> -Ed
I don't think you can get the parameters of a signal using 
QSignalMapper. If you need the id and the parameters of a set of signals 
connected to a single slot, use the sender method.
MyWidget *w = qobject_cast<MyWidget *>?(sender());
if(w != (MyWidget *)NULL) {
}
It is important to use qobject_cast to verify that the sender of the 
correct type.