C++ and VBA: Building a registration-free COM DLL? - c++

Question

in short:
Is it possible to create a C++-based COM component that I can reference and use from VBA, without needing to register the DLL (in windows registry)?
In long:
I'm a COM novice, so maybe what I'm tryong to do here structurally doesn't work or doesn't make sense, but:
I want to create a C++ COM library that is usable from VBA registration-free.
So I've created an C++ ATL project in VS, added a custom COM type (MyClass) and added a test method to it ("AddNumbers", taking 2 long parameters and returning 1).
When building this project, I'm getting an error "Failed to register output. Please try anebling Per-User Redirection or register the component from a comment prompt with elevated permissions", likely because I'm running Visual Studio without admin permissions. However, the DLL builds fine, I assume it's just not registered after building it.
Right, so when I reference this DLL in my VBA project (Tools -> Referewnces -> Browse... and add), intellisesne works, i.e. VBA knows the type "MyClass", knows it has a method "AddNumbers" and so on.
But, it can't instantiate it:
Sub test()
Dim q As MyClass
Set q = New MyClass ' This will fail: "Run-time error '429': ActiveX component can't create object"
End Sub
Why is that? Am I right in assuming it likely fails because this COM component isn't properly registered on the machine?
If so, can I somehow circumvent this? I've read some infos about registration-free .NET based COM components, but I have no idea if this also works - or is even needed?! - for C++ based components.
MyClass.h
// MyClass.h : Declaration of the CMyClass
#pragma once
#include "resource.h" // main symbols
#include "ATLProject4_i.h"
#if defined(_WIN32_WCE) && !defined(_CE_DCOM) && !defined(_CE_ALLOW_SINGLE_THREADED_OBJECTS_IN_MTA)
#error "Single-threaded COM objects are not properly supported on Windows CE platform, such as the Windows Mobile platforms that do not include full DCOM support. Define _CE_ALLOW_SINGLE_THREADED_OBJECTS_IN_MTA to force ATL to support creating single-thread COM object's and allow use of it's single-threaded COM object implementations. The threading model in your rgs file was set to 'Free' as that is the only threading model supported in non DCOM Windows CE platforms."
#endif
using namespace ATL;
// CMyClass
class ATL_NO_VTABLE CMyClass :
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<CMyClass, &CLSID_MyClass>,
public IDispatchImpl<IMyClass, &IID_IMyClass, &LIBID_ATLProject4Lib, /*wMajor =*/ 0xFFFF, /*wMinor =*/ 0xFFFF>
{
public:
CMyClass()
{
}
DECLARE_REGISTRY_RESOURCEID(106)
BEGIN_COM_MAP(CMyClass)
COM_INTERFACE_ENTRY(IMyClass)
COM_INTERFACE_ENTRY(IDispatch)
END_COM_MAP()
DECLARE_PROTECT_FINAL_CONSTRUCT()
HRESULT FinalConstruct()
{
return S_OK;
}
void FinalRelease()
{
}
public:
STDMETHOD(AddNumbers)(LONG Num1, LONG Num2, LONG* ReturnVal);
};
OBJECT_ENTRY_AUTO(__uuidof(MyClass), CMyClass)
MyClass.cpp
// MyClass.cpp : Implementation of CMyClass
#include "stdafx.h"
#include "MyClass.h"
// CMyClass
STDMETHODIMP CMyClass::AddNumbers(LONG Num1, LONG Num2, LONG* ReturnVal)
{
// TODO: Add your implementation code here
*ReturnVal = Num1 + Num2;
return S_OK;
}