Use OCX without registering it

Question

Is it possible to use an ocx (ActiveX Control) on a winform (probably adding it programatically) without first having the ocx registered with regsrv32?

What I'm trying to achieve is to enable xcopy installation. I've had the "AxInterop..dll" and "Interop..dll" file generated from my dev machine.

I've seen the possibility of calling a COM dll without first registering it (ProSysLib, according to the author, but I haven't tested it yet), since ocx is also COM based, thus I assume that there must be some way to do that as well.

Answer 1

Yes, this can be done. You must assume your application will only be deployed on Windows XP (or Windows Server 2003) or later, and then you can use what is called 'registration free COM' to make this happen.

Essentially what you do is create a manifest file for the ActiveX control DLL so the Windows loader & COM DLL's know what its registration is without having to put that in the registry.

A walkthrough of what to do is in this article on MSDN: Registration-Free Activation of COM Components: A Walkthrough

"Step 6" and "Step 7" in that article contain everything you will need.

I just tried this out on one of my own C# programs that uses a Microsoft ActiveX grid control (the old "MS Flex Grid") and it works just fine. Make sure you create a manifest file for both your application and the COM DLL, and substitute the appropriate GUIDs in the right places. You may need to use OLEVIEW to dig out the right IDs to use from the ActiveX DLL if you don't have them handy.

Answer 2

Be warned that apparently using registry-free COM for COM components authored in .NET can randomly cause crashes on Windows XP!

Links: Stackoverflow question where I learned this, Microsoft knowledgebase article referred to in that question. There is a hotfix but you aren't allowed to redistribute it.