Calling 32bit COM from c# running in 64bit mode

I have a 3rd party COM object(32 bit) that I need to call from my c# application (64 bit). I know I have to run the COM object in a separate process. This COM object has many classes implemented in it, so I'm trying to avoid writing my own remoting wrapper that exposes all the methods. COM+ seems to be the most straightforward solution. I opened the Component Services menu, created a new COM+ Application, added my COM object as a component to this application. Everything seemed to import beautifully.

In my C# application, I added the original COM object as a reference (which automatically generates the type library). Using the type library reference, I can create objects from from the COM+ component (I see them begin to spin in the Component Services window), but when I try to access on of the methods of the object, I get an error saying the interface is not registered.

Does anyone have a clue? I went back and ran regsvr32 on the COM object, but I don't think it was necessary, and it didn't help. Is my usage in C# correct? VS2008 autocomplete had no problem seeing those methods.

The exact exception is: "Interface not registered (Exception from HRESULT:0x80040155)"

Unclear about exactly what the permissions and roles are about in the Component Services, I tried setting up the COM+ object identity to run under the System Account, both as a local service and as interactive user. I've added Everyone as a user in the Roles. Everything is running locally, so there shouldn't be an issue with file privileges or anything like that.

I also want to reiterate that this COM object contains many classes. I successfully instantiated one class object in my client and set some property values. I also successfully instantiated another class object, but received this exception when attempting to call a method of this second object .... so I don't think there is an issue with which registry my COM object is registered in.

We had a similar situation, working with a COM dll from VFP.

It all depends on rights and permissions, like Yahia says. We got it working by doing this:

• Install VFP oledb 9 drivers (dunno what you have so probably not required).
• give Network Service IIS_IUSR full control on the COM folder (required so the DLL can do some logging in its own folder, when called from the website).
• run regsvr32.exe "c:\xxx\yourfile.dll" -> this should be successful!
• Create COM+ application, and add the DLL as a part
• Set the application COM+ credentials on a user wigh sufficient rights

and we had to do some more settings on rights in application pool / IIS, but thats not required for you I guess.

Anyways, just make sure you have enough logging, make sure the dll is registered, and after that its all about rights rights rights..

Good luck with it!