Access Methods from ATL DLL File in C #

Question

I worked with an attempt to link some C ++ code and wrap it inside a COM object for access through C #. I created an atl project and added a simple method like Add (double a, double b). Below is the code from my atl.h file:

// atl.h : Declaration of the Catl
#pragma once
#include "resource.h"       // main symbols

#include "com_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 and allow use of it 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



// Catl

class ATL_NO_VTABLE Catl :
public CComObjectRootEx<CComSingleThreadModel>,
public CComCoClass<Catl, &CLSID_atl>,
public Iatl
{
public:
Catl()
{
}

DECLARE_REGISTRY_RESOURCEID(IDR_ATL)

DECLARE_NOT_AGGREGATABLE(Catl)

BEGIN_COM_MAP(Catl)
COM_INTERFACE_ENTRY(Iatl)
END_COM_MAP()



DECLARE_PROTECT_FINAL_CONSTRUCT()

HRESULT FinalConstruct()
{
    return S_OK;
}

void FinalRelease()
{
}

public:

STDMETHOD(Add)(DOUBLE a, DOUBLE b);
};

OBJECT_ENTRY_AUTO(__uuidof(atl), Catl)

Below is the atl.cpp file

// atl.cpp : Implementation of Catl

#include "stdafx.h"
#include "atl.h"

STDMETHODIMP Catl::Add(DOUBLE a, DOUBLE b)
{
// TODO: Add your implementation code here

return a + b;
}

Inside my C # file, I call dll ... after I referenced it ... it sees a DLL, but no methods assigned. That's my problem. Heres the code from program.cs

sing System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;

namespace sharpdll
{
class Program
{
    [DllImport("com.dll")]
    public static extern double Add(double a, double b);

    static void Main(string[] args)
    {
        Add(2, 3);
    }
}
}

Debugging interrupts when adding (2, 3); Says "Could not find an entry point named" Add "to the DLL" com.dll "". Any ideas?

Answer 1

DllImport for PInvoke (for native Win32 DLLs).
Do you want COM Interop.

ATL com, , .Net COM-.

ATL ++ ++/CLI.

, ,