Solved

Problem with RegisterActiveObject

Posted on 2008-10-08
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Last Modified: 2012-06-21
I'm trying to get RegisterActiveObject to behave. Doing it the way that's been described here

type TAutoClass = class (TAutoObject,IMyInterface)
private
  Cookie : longint;
public
  procedure Initialize; override;
...
procedure TAutoClass.Initialize;
  begin
    inherited Initialize:
    RegisterActiveObject (Self As IUnknown, Class_MyClass, ActiveObject_Weak, Cookie);
  end;

gives two 'incompatible types', IUnknown/TAutoClass and Ole2.TGUID/System.TGUID.
I can make it compile OK by writing

    RegisterActiveObject (IUnknown(Self), Ole2.TGUID(Class_MyClass), ActiveObject_Weak, Cookie);

but when I actually use the thing something goes drastically wrong and I'm seeing recursive calls
into the initialize routine, the RegisterActiveObject seems to be causing a new Initialize. What basic
mistake am I making here?
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Question by:mikrobe
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2 Comments
 
LVL 27

Expert Comment

by:BigRat
ID: 22677142
From Delphi 5 help :-

When creating an OLE automation object (an object derived from the TAutoObject class in the Oleauto unit) the file that defines that object must call Automation.RegisterClass, passing a record of type TAutoClassInfo. The Automation manager then handles all interactions between the automation object and the OLE automation API.


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Accepted Solution

by:
mikrobe earned 0 total points
ID: 22677243
I think the TAutoObject I'm using here is actually the one defined in ComObj. However I do think there is some confusion about which versions of the various pieces involved are being used (hence the confusion about the TGUID type). The Ole2 module was being referenced in my 'uses' (for historical reasons :-) and removing that not only persuaded Delphi to accept the original syntax but also got rid of the inifinite loop in the Initialize routine. No idea what the problem *really* was other than that Delphi was obviously interpreting things the wrong way when Ole2 was in the mix.
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