[Mono-dev] Creating Managed COM objects from C++ (on linux).

[Tom Hindle]

On Fri, 2008-12-19 at 17:07 -0500, Bill Holmes wrote:
> We have dealt with this by registering a global class factory method
> (that is implemented in C#) with native C++ code.
> 
> I assume you are hosting the mono runtime?

Yes.

> 
> Take a look at the poor code example below and see if that gives you the idea.

Thanks for the idea!
I think I would still prefer being able to do it via the mono c API and
so not having an assembly coupled with my COM object, but a least I now
have a solution if I can't do that.

I guess I can use reflection, to search in the assembly for the class
associated with the CLSID, in the implementation of
ManagedCOMFactoryCreateObject to make it generic.

Thanks,
Tom

> 
> -bill
> 
> /* C++ code */
> void cppMain ()
> {
> 	// Init Mono Runtme
> 	
> 	// Call managed InitManagedCOMFactory
> 	
> 	IUnknown* pObj;
> 	ManagedCOMFactoryCreateObject (CLSID_MyObj, &pObj);
> 	
> 	IFoo* pFoo;
> 	pObj->QueryInterface (IID_IFoo, (void**)&pFoo);
> 
> 
> }
> 
> uint (*ManagedCOMFactoryCreateObject) (GUID*, IUnknown**);
> 
> void RegsterManagedCOMFactoryCreateObject (void* ptr)
> {
> 	ManagedCOMFactoryCreateObject = ptr;	
> }
> 
> 
> 
> 
> /* C# code */
> 
> void InitManagedCOMFactory ()
> {
> 	RegsterManagedCOMFactoryCreateObject (ManagedCOMFactoryCreateObject);	
> }
> 
> uint ManagedCOMFactoryCreateObject (guid g, [MarshalAs (IUnknown)] out
> object retObj)
> {
> 	if (g == myGuid)
> 		retObj = new MyObject ();
> }