About callbacks

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6 total messages Started by Goumatianos Fri, 23 Mar 2001 18:15

#593

Author: Goumatianos
Date: Fri, 23 Mar 2001 18:15

31 lines
1708 bytes

I have experience in Delphi , but in c++builder
just 2 months. I can't develop a callback method in midas project.
At server's side (in server.tlb) I created a interface "IEbClient"
(IDispatch) and its
method "CallbackClient".

In delphi, at client's side (clientfrm) is:
-------------------------------------------------------------
type
  TCallBack = class(TAutoIntfObject, IEbClient)
  procedure CallBackClient(ActionID,UpdateKind: Integer; aValue:
oleVariant); Safecall;
  end;
.....

procedure TCallBack.CallBackClient(ActionId,UpdateKind: Integer;aValue:
OleVariant);
Begin
Case ActionId of
0: clientform.Close;
1: Clientform.Updatedata(ActionID,UpDateKind,aValue);
end;
end;

----------------------------------------------------------------

But I couldn't translated it in c++builder.

Thanks in advance
Nikitas
( email - goumatianos@hotmail.com )

Re: About callbacks

#596

Author: Mark Cashman
Date: Tue, 27 Mar 2001 00:54

12 lines
1243 bytes

Hi, Nikitas!

What error message do you get?

------
Mark Cashman (TeamB - C++ Builder), creator of The Temporal Doorway at
http://www.temporaldoorway.com
- Original digital art, writing, music and more -
C++ Builder / JBuilder Tips and The C++ Builder Programmer's Webring
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------

Re: About callbacks

#598

Author: Goumatianos
Date: Tue, 27 Mar 2001 16:36

25 lines
1444 bytes

I tried it in many ways...
The message was"access violation..."
I think the proplem is in clients side.
Something is wrong with the declaration.
In delphi that works perfectly is:

type
  TCallBack = class(TAutoIntfObject, IEbClient)
  procedure CallBackClient(ActionID,UpdateKind: Integer; aValue:
oleVariant); Safecall;
  end;

but in c++ builder I tried in many ways..such as..
class TCallback : IEbClient
{....};

or

class IEbClient  : IDispatch
{.....}

I don't know how to declare "TCallBack = class(TAutoIntfObject, IEbClient)"
(two classes..)

thanks

Re: About callbacks

#599

Author: Mark Cashman
Date: Wed, 28 Mar 2001 03:42

15 lines
1595 bytes

Unfortunately, you cannot declare multiply inherited descendants of VCL
classes. This is a big problem when dealing with interfaces.

However, your access violation is probably due to a programming or
memory usage error, since the above condition does not allow the program
to compile.

------
Mark Cashman (TeamB - C++ Builder), creator of The Temporal Doorway at
http://www.temporaldoorway.com
- Original digital art, writing, music and more -
C++ Builder / JBuilder Tips and The C++ Builder Programmer's Webring
(Join us!)
http://www.temporaldoorway.com/programming/index.htm
------

Re: About callbacks

#600

Author: Goumatianos
Date: Wed, 28 Mar 2001 04:16

6 lines
1260 bytes

So I can do callback in Delphi , but there isn't way to do it in c++Builder?
Then, the only way is to convert the client as COM server, isn't it?

Thanks , but before I convert the client to com server, I will try some
other ways. If I achieve it (without converting to a second com server), I
will post it here.

Re: About callbacks

#664

Author: Peter Burger
Date: Wed, 11 Apr 2001 06:35

32 lines
1942 bytes

thats sounds very interesting,

i'm looking also for a technique to realize callbacks with c++ builder
and didn't find any solution till yet.

my trips ends allways at the state of :


=>  I don't know how to declare "TCallBack = class(TAutoIntfObject,
IEbClient)"
    (two classes..)


so it would be very nice if some�one find a solution of the callback - c++
builder problem


peter

--

"Goumatianos" <goumatianos@hotmail.com> schrieb im Newsbeitrag
news:3ac1640d_2@dnews...
> So I can do callback in Delphi , but there isn't way to do it in
c++Builder?
> Then, the only way is to convert the client as COM server, isn't it?
>
> Thanks , but before I convert the client to com server, I will try some
> other ways. If I achieve it (without converting to a second com server), I
> will post it here.
>
>

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