How to implement interface of C# use COM of native C++?

i'm using .net core in cross platform, include windows , linux.

i can't use atl.

i embed the. net core executable program.

i hope expose c++ class instance pointer .net core(c#), , convert interface of c#.

c++:

class foo : public idispatch, public imanagedobject, public iinspectable...{} fobj;

extern "c" __declspec(dllexport) foo* winapi gettestobject(){return new foo;}

c#:

[dllimport("foo.dll")]

static extern intptr gettestobject();

[guid("48df8e89-57de-3599-ad7c-b49500ef01c0")]
interface itest
{
int func();
}

main(){

    var v = gettestobject();
    var obj = (itest)marshal.getobjectforiunknown(v);
    obj.func();// exception

dynamic dobj = marshal.getobjectforiunknown(v);

dobj.func();// ok, idispatch::invoke called

}

i hope implement interface test of c#.

[interfacetype(cominterfacetype.interfaceisidispatch)]

interface itest{...}

is ok, c++::foo::invoke(idispatch) called.

.NET Framework > Common Language Runtime Internals and Architecture

Gain