Can I extend MMCCtrl object's interface via C++?

Question

Can I extend MMCCtrl object's interface via C++?

Sergey Kolesnik 1

I have a legacy mmc C++ application that uses MMCCtrl object within a DHTML taskpad:
<head> <object id="taskctrl" classid="CLSID:545AE700-50BF-11D1-9FE9-00600832DB4A"> </object> </head>

I expected that I could add some methods and override MMCCtrl's IDispatch to make them visible to JavaScript. But I can't find any info on C++ interfaces that are used for MMCCtrl (or any C++ documentation at all for MMC in that regard).
Moreover, IComponent interface does not seem be the interface I need, since it does not provide any of the MMCCtrl's methods that are described here. And it also does not inherit from IDispatch...

So is it even possible to add methods to MMCCtrl's interface for a particular mmc application?
Does MMCCtrl work in some other way than implementing IDispatch?

RLWA32 52,571 Reputation points

2021-11-19T13:34:52.347+00:00

Maybe you can use IDispatchEx (used with JScript and VBScript)? The interface is documented in the DispEx.h header file. Here's a link to an old Dr Dobbs article about it https://www.drdobbs.com/active-scripting-newsletter/184404200
Sergey Kolesnik 1 Reputation point

2021-11-19T15:59:04.47+00:00

The way JS Objects are loaded implies that a dll with CLSID has to be registered. And creating and registering a new component is too much of a hassle. So the question is explicitly about MMCCtrl
RLWA32 52,571 Reputation points

2021-11-19T16:32:00.37+00:00

MMCCtrl documentation is here - mmcctrl-control. Details are in the Windows SDK .h and .idl files mentioned in the link. The object is hosted in cic.dll and you can examine the type library with the oleview.exe SDK utility.

Also, maybe you could use the TreatAs registry redirection to instantiate your own object -- Good article at hooking-com-classes
RLWA32 52,571 Reputation points

2021-11-22T10:25:51.99+00:00

@Minxin Yu -- This is a question about COM so its not clear to me why the tag was changed to not-supported. For future reference kindly advise which tag should be used for COM related questions.
Minxin Yu 13,516 Reputation points Microsoft External Staff

2021-11-23T01:22:10.677+00:00

@RLWA32 Hi, tag windows-api can be used for COM related questions.
RLWA32 52,571 Reputation points

2021-11-23T02:21:11.287+00:00

Thank you for your answer to my question about the tags. Perhaps you would consider editing the question to change the tag to windows-api to make the information about the TreatAs registry redirection and the link to information about hooking COM classes more accessible to anyone who might be interested.