Re: How to fire a com event

"Maurice" <manker@tpg.com.au> wrote in message 
news:47df71f1@newsgroups.borland.com...

> Create a new VCL Forms project
> Create a COM Object (X) with Event support code enabled

The only reason to do that is if the COM object is going to be used by 
external programs.  In which case, you should use an Automation Object, not 
a COM object.

Beyond that, there is no point in creating a COM object for private use 
within the same program that defines it.  If you are going to expose access 
to a COM object for other programs to use, then they will create the object 
instances, not you.  Simply keep track of the instances that get created, 
such as by having TXImpl's constructor and destructor add/remove the 
object's 'this' pointer to a list somewhere in your code.  You can then run 
through the instances when needed, calling Fire_MyEvent() on them.


Gambit 

"Maurice" <manker@tpg.com.au> wrote in message 
news:47e0471d$1@newsgroups.borland.com...

> But I am still puzzled -- I thought it was the job of
> Fire_MyEvent() to iterate through the list of clients stored
> in the TEvents_X:ConnectionPointContainer and call
> MyEvent() on each

It is supposed to, but the connection point logic is not implemented 
correctly, at least in my experience.  Each client ends up with its own 
connection point list, so Fire_...() methods only have 1 client object to 
ever call into, and thus the need to call Fire_...() on each client manually 
one at a time manually.  At least, that has always been my experience in all 
of my own COM servers.  The connection point list is not as global as it is 
supposed to be.


Gambit 

I am sure there is a simple answer to this: in BDS 2006 (C++) I do the 
following

Create a new VCL Forms project
Create a COM Object (X) with Event support code enabled
Add a method (MyEvent) to the IXEvents interface
Include the X implementation header in the form unit
Place a button on the form with the following code
//---------------------------------------------------------------------------
void __fastcall TForm1::FireEventClick(TObject *Sender)
{
    Fire_MyEvent();
}
//---------------------------------------------------------------------------

Of course it doesn't work because is not a global function but a method of 
the TEvents_X template class
If a method is added to the IX interface and its definition includes a call 
to Fire_MyEvent(); then there's no problem.

I have tried all sorts of things to create a pointer to an instance of this 
class, eg

CComPtr<TEvents_X<TXImpl> > ptr;  // or  CComPtr<X> ptr;
ptr.CoCreateInstance(CLSID_X);
ptr->Fire_MyEvent();

but to no avail. What am I doing wrong?

Thanks - Maurice 

"Remy Lebeau (TeamB)" <no.spam@no.spam.com> wrote in message 
news:47e0010a$2@newsgroups.borland.com...

>   Simply keep track of the instances that get created, such as by having 
> TXImpl's constructor and destructor add/remove the object's 'this' pointer

> to a list somewhere in your code.  You can then run through the instances 
> when needed, calling Fire_MyEvent() on them.
>
Great! That does what I want.

But I am still puzzled -- I thought it was the job of Fire_MyEvent() to 
iterate through the list of clients stored in the 
TEvents_X:ConnectionPointContainer and call MyEvent() on each:

template <class T> HRESULT
TEvents_X<T>::Fire_MyEvent(void)
{
  T * pT = (T*)this;
  pT->Lock();
  IUnknown ** pp = m_vec.begin();
  while (pp < m_vec.end())
  {
  if (*pp != NULL)
  {
      m_EventIntfObj.Attach(*pp);
      m_EventIntfObj.MyEvent();
      m_EventIntfObj.Attach(0);
  }
  pp++;
  }
  pT->Unlock();
  return S_OK;
}