Event Programming Question

I have a project that is essentially a notifier to listening applications. The base class is a generic C++ class that simply manages data. When the data changes it needs to notify the listeners that something has changed. One of the methods of notification is events.

I have already implemented an ATL class that has events within it. How does my base class notify the ATL class to fire the events?

Sorry if this is simple - I think I am trying to make it more difficult then it actually is. Thanks in advance!

Usually the base class calls a virtual function that is implemented in your ATL class. The ATL class then raises the event with Fire_[eventname](args).

How does the base class call functions within another class?

I created public virtual functions which call the corresponding Fire functions within my ATL class. Should I have created the virtual functions within my base class?

Thanks for your help.

See the "Observer pattern" at http://en.wikipedia.org/wiki/Observer_pattern

Mike

Thank you all for your help thus far. I am still very confused however, and maybe it is because I am not being clear (or just am very confused and have my process implemented incorrectly).

My base class is a generic C++ class which handles data. Within my project I have implemented ATL interfaces for other applications to communicate to me through to access data and to be notified when it changes. These are working fine, but I need to add one more option which is to raise an event when data changes. Is there a way to raise an event without an ATL class that everyone listening can hear?

No.

class MyBase
{
virtual void DoFireWhatever(string strArg) ;
};

class ATL_NO_VTABLE YourAtlClass:
...
{
...
void DoFireWhatever(string strArg)
{
Fire_Whatever(strArg);
}
...
}

The base class can just call DoFireWhatever and the ATL class takes it from there.

Quote:

---

Originally Posted by drm15

I have already implemented an ATL class that has events within it. How does my base class notify the ATL class to fire the events?

---

Do you mean, you have implemented connection point container and connection point for the event notification ?

I apologize if my terminology is not correct (I assume it is not). I believe you are correct, I have implemented a connection point container. I am trying to follow the tutorials for creating an ATL interface class with connection points. I did this because that is the only way I know how to create global events to any attached process. I am trying to raise these events from my base class within this ATL class.

I am currently trying to implement the previous suggestion to yours, but if you have anything I am open to suggestions. I seem to be very stuck on this and it doesn't seem like it should be this difficult.

I have attached my ATL class to try to make more sense. If anyone has an idea of how my base class can fire the events within my ContextParticipant class I am open to anything.

Thank you all for your help!

Your code doesn't contain the connection point implementation.
I suggest reading this article.

http://www.codeguru.com/cpp/com-tech...cle.php/c3623/