Fire Event from outside the COM Method - COM Discussion Boards

Fire Event from outside the COM Method

28-May-02 7:28

Did you use the Application independant ProgID ???
--> 'Word.Application'

Dont use any predefined id's use 'CLSIDFromProgID' to get the clsid.

Re: automation

31-May-02 4:21

Thanks for your answer.
I user for word :
CLSID clsid;
CLSIDFromProgID(L"Word.Document",&clsid); //not working
for excel :
CLSIDFromProgID(L"Excel.Sheet" ,&clsid); //working good

Koep28-May-02 3:33

28-May-02 3:33

Hi again,

now i have wrote a Excel VBS Script, to test my COM Server.
I can fire an Event within the called Method. Then an Event
in the Excel Macro is raised. So far so well...

Now i want to raise an event from outside of the called COM Method.

Step 1: Excel VBS Macro calls a Method from the Server
Step 2: the server sends the inquiry further (to Socket) and returns
- the VBS macro goes through the following Loop
* While iCounter <> 0
* DoEvents
* Wend
Step 3: The answer ( from socket ) is coming into the Server
Step 4: A Function calls the ComInterface-Eventmethod
Step 5: the Excel VBS macro should raise the event, but it doesn't

does any have an idea, why it does not function?

Marco

Len Holgate30-May-02 19:50

30-May-02 19:50

Are you marshalling the com event interface to the thread that does the server call correctly? Take a look at my async mailslot article as this deals with the problem of firing events from outside sources.

Len Holgate
www.jetbyte.com
The right code, right now.

Koep30-May-02 21:08

30-May-02 21:08

Thanxs for the answer,

the Function uses a pointer of the event interface. Is this the problem ?

I will try your suggestion !

Marco

Len Holgate30-May-02 21:14

30-May-02 21:14

You need to either marshal the event interface into the thread that needs to call back (which I always found was unreliable) or have the thread that needs to call back do so via an interface that effectively marshals the callback into the thread that VB registered the event sink in. My article does it the second way and works fine.

Len Holgate
www.jetbyte.com
The right code, right now.

Koep30-May-02 23:51

30-May-02 23:51

Hi,

i've tried to marshal the event interface from the Interface Impl. class.

// this is CPort ( implementation from "interface IPort : IDispatch" )

HRESULT hr = CoMarshalInterThreadInterfaceInStream(DIID__IPortEvents,(_IPortEvents*)this,&pStream);

But "(_IPortEvents*)this" doesn't get the Event Interface.

I can only marshal the IPort Interface. How can i get the pertinent Eventinterface ?

Marco

Len Holgate31-May-02 0:01

31-May-02 0:01

The code in the article explains what you need to do and what you need to be aware of.

Your impl class probably doesn't implement the event sink interface, there would be no reason for it to, after all the interface is for users of your class to implement so that they can sink your class's events. You either have to marshal the interface that the client registers with you (during advise), but this is made complex if you happen to be using the ATL stuff to do the connection point management for you. OR you need to implement a new interface that you use to communicate between your worker thread and your main object's thread. See the article for a complete implementation. It's non trivial (hence the need for an article). Smile | :)

Len Holgate
www.jetbyte.com
The right code, right now.

Koep31-May-02 1:00

31-May-02 1:00

Hi again,

now it seems to work ! I've tried your first suggestion.
I take the "m_vec" to get the IDispatch Interfaces, like the EventProxy Code it does. Then I marshal these Interfaces to global Variables.
Finally i unmarshal these interfaces and call the "invoke" Funktion, to
fire the event.

Your 2. Solution seems to extensively for my program.

Marco

Len Holgate31-May-02 1:11

31-May-02 1:11

Koep wrote:
now it seems to work ! I've tried your first suggestion.
I take the "m_vec" to get the IDispatch Interfaces, like the EventProxy Code it does. Then I marshal these Interfaces to global Variables.
Finally i unmarshal these interfaces and call the "invoke" Funktion, to
fire the event.

Sounds good! Glad it works.

Len Holgate
www.jetbyte.com
The right code, right now.

SafeArray

Sameer Maggon27-May-02 20:18

Sameer Maggon

27-May-02 20:18

Hi,
I want to return Binary data i've read from a file.
I know it can be done by safe array.. can nebody give me some hint on how to do that

Regards
Sameer

Re: SafeArray

Prem Kumar28-May-02 7:14

28-May-02 7:14

Use the type VT_U1 to store the binary data.

use IStream instead

soptest28-May-02 9:53

soptest

28-May-02 9:53

soptest

Re: SafeArray

Len Holgate30-May-02 21:54

Fire COM Event from MFC Class

30-May-02 21:54

I do something similar (return binary data in a safe array) in my COM Mailslots article. The code in question is:

STDMETHODIMP CMailslotData::Read(VARIANT *ppResults)
{
   if (!ppResults)
   {
      return E_POINTER;
   }

   return CreateSafeArray(m_pData, m_length, ppResults); 
}

where m_pData points to the bytes of data and m_length is the number of bytes we have.

HRESULT CreateSafeArray(
   BYTE *pData,
   DWORD dataLength,
   VARIANT *ppResults)
{
   SAFEARRAYBOUND sab;
   sab.cElements = dataLength;
   sab.lLbound = 0;

   SAFEARRAY *pSa = SafeArrayCreateEx(VT_UI1, 1, &sab, 0);
   
   PVOID pvData;
   
   HRESULT hr = SafeArrayAccessData(pSa, &pvData);
   
   if (SUCCEEDED(hr))
   {
      ::CopyMemory(pvData, pData, dataLength);
   
      hr = ::SafeArrayUnaccessData(pSa);
   }

   if (SUCCEEDED(hr))
   {
      ::VariantInit(ppResults);
           
      (*ppResults).parray = pSa;
      (*ppResults).vt = VT_ARRAY | VT_UI1;
   }

   return hr;
}

Hope this helps.

Len Holgate
www.jetbyte.com
The right code, right now.

Koep27-May-02 4:59

Re: Fire COM Event from MFC Class

27-May-02 4:59

Hello,

i have to raise an event from outside the COM Class.
The Eventnotifier is a CObject MFC Class und should
raise the event in the COM Server Class. I have no
idea which header i should include to make this
possible.

MFC-Class should call CProxy_IXXXEvents ( Fire_OnXXXX )

Can anybody help me ?

Marco

Prem Kumar28-May-02 7:22

Re: server to client calls

28-May-02 7:22

Hi,

The best way would be to pass the pointer to the COM class
itself. Since you would not know in which COM class instance
you want to fire the event.

And then ofcourse it is as simple as Calling
pObject->FireEvent()

server to client calls

26-May-02 23:08

Hi all

I have a question regaring DCOM basic knowledge

the Q is : is it possible to create a client server application were the server can call a client without the client calling the server first.? is there any GOOD article to show me how to do so?

further more is DCOM works only over TCP/IP ?

Confused | :confused:

Prem Kumar28-May-02 7:20