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Callback and Thisback Function call parameters [message #43429]

Tue, 29 July 2014 11:50

NilaT
Messages: 70
Registered: November 2011
Location: Austria

Member

Hi everybody, I've got a new question for you, which is driving me nuts.
Callbacks and Thisbacks are quite difficult for beginners, but I think I got them... almost Wink

One thing is still unclear to me.
How can I add Parameters to a Function which is called, when a callback occurs?

For example:
Somewhere I got this:

Callback2<Point, Point>	 WhenProductChanging;

and then I got this, somewhere

...
WhenProductChanging(p1, p2);
...

And somewhere else I got this:

xxx.WhenProductChanging = THISBACK(OnProductChanging);

And finally, I got the function itself:

void yyy::OnProductChanging(Point firstP, Point secondP)
{ /* do something */
}

Now, what I want is to add another parameter to my "OnProductChanging" Method, like for example:

void yyy::OnProductChanging(Point firstP, Point secondP, int newParameter)
{ /* do something */
}

So I thought I have to change the THISBACK to THISBACK1 and pass the parameter after the Methodname, like this:

xxx.WhenProductChanging = THISBACK1(OnProductChanging, 1);

But this doesn't work, because it seems that all necessary parameters come from the callback. How can I pass another parameter, which is defined somewhere else and not known in the "callback-calling" function?

Thanks in advance!

[Updated on: Tue, 29 July 2014 11:51]

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