How to call a given function from an assembly in managed c++?

Question

C++ / C#

There is an assembly in C#, which has a public method that accepts System.Object, treating it like a COM object.
From C#, this method is used like this:

var ComType = Type.GetTypeFromProgID("Excel.Application");
var obj = Activator.CreateInstance(ComType);
ProcessObject(obj); // ProcessObject(System.Object objToProcess)

The ProcessObject function accepts an object, treating it like an IDispatch.
Challenge: call this function from a managed c++ assembly. I have a normal (unmanaged) pointer to IDispatch.

MyClass::MyMethod(IDispatch* pDesigner)
    {
  // здесь должен быть вызов функции ProcessObject 
        // из сборки на С# с передачей туда указателя pDesigner
    }

Somehow you need to convert it to System.Object and pass it to C#. Interested in the right way to do it.

Answer 1

The toaster is traditionally bad with specific answers. Only reasoning about "you are doing it wrong"
Here is a specific answer, in case it is useful to someone:

// IUnknown* pDesigner
IntPtr handle = IntPtr(pDesigner);
Object^ managedObject = System::Runtime::InteropServices::Marshal::GetObjectForIUnknown(handle);

Answer 2

In general, read about Ole Automation first. For your task, you are using slightly the wrong thing. Then look at how it's done in .NET, there are tools out there. I did it myself in C ++ and C #, so in C ++ it's hell, it's better not to go there. But in C#, everything is fine, you don’t even have to think about COM, Ole in general.
UPD. At first I cheated with the version, it was on .net 1.1.