Issue with initializing COM object

Question

I compiled the following VB code and got the dll ("TestVB.dll") and tlb ("TestVB.tlb") files as output.

Imports System
Imports System.Runtime.InteropServices

Namespace TesterNS

    <ComVisible(True),
    Guid("4B673F5A-A953-4C20-9A90-8F94ED2F6DDF"),
    InterfaceType(ComInterfaceType.InterfaceIsIDispatch)>
    Public Interface _Tester
        Function GetMonth() As Integer
    End Interface

    <ComVisible(True),
    Guid("FEC833EE-37E9-4406-9344-8A8BD5C43B07"),
    ClassInterface(ClassInterfaceType.None),
    ProgId("Tester.Numbers1")> Public Class Tester
        Implements _Tester

        Public Tester()

        Public Function GetMonth() As Integer Implements _Tester.GetMonth
            GetMonth = DateTime.Now.Month
        End Function
    End Class

End Namespace

I selected the

Register for COM interop

option in the project settings for the VB project.

I am trying to access the above functionality from a C++ code. I included the following import statement in the stdafx.h file in C++.

#import "TestVB.tlb" no_function_mapping, no_namespace, named_guids

and trying to access the COM object as follows:

HRESULT hr = CoInitialize(NULL);
_TesterPtr t1 = NULL;
CLSID cls;
std::string s = "";
bool flag = false;
hr = CLSIDFromProgID(L"Tester.Numbers1", &cls);
if (SUCCEEDED(hr))
{
    hr = CoCreateInstance(cls, NULL, CLSCTX_INPROC_SERVER, __uuidof(_Tester), (void**)&t1);
    if (SUCCEEDED(hr))
        s = "success";
    else
        s = "fail";
}

I am seeing hr = REGDB_E_CLASSNOTREG Class not registered error after making the CoCreateInstance call.

I am not sure what I am doing wrong.

Answer 1

In my C++ application, there is a call to AfxOleInit() before CoInitialize(NULL). If I remove the call to CoInitialize(NULL), I was able to get it working.