Calling unregistered .net dll from c++.

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Hello

How do i call a dll which is created in .net framework 2.0 in C++,
although the dll is not COM registered. With registering the dll i can call the dll with the following code.

#include "stdio.h"
#include "conio.h"

#import "C:\Documents and Settings\Desktop\d\test.dll.tlb"

using namespace test;

#include <string>;
using namespace std;

void main(int argc, char* argv[])
{
  HRESULT hr = CoInitialize(NULL);
  IPayProcess* pTest = NULL;
  hr = CoCreateInstance(__uuidof(Pay), NULL, CLSCTX_INPROC_SERVER, __uuidof(IPayProcess), (void**)&pTest);
  pTest->;PayProcess("abc");
}
</string>

If I don't register the dll it gives the object reference not set to an instance error.

Thanks

Posted 28-Oct-10 1:09am

dharmeshpatt

Updated 28-Oct-10 1:12am

JF2015

v2

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E.F. Nijboer · Answer 1 · 2010-10-28T01:36:00

Solution 1

Have a look Registration-Free COM Interop:
http://msdn.microsoft.com/en-us/library/fh1h056h.aspx[^]

And also the DllImportAttribute Class:
http://msdn.microsoft.com/en-us/library/system.runtime.interopservices.dllimportattribute.aspx[^]

Good luck!

Posted 28-Oct-10 1:36am

E.F. Nijboer

Richard MacCutchan · Answer 2 · 2010-10-28T01:54:00

You can use CoLoadLibrary() to load the dll and obtain a reference to it with the following code; just add the path to your dll to the first parameter. Also change references to CLSID_CGeneric and IID_IGeneric to your own GUID references.

Note that you should always check the return code from CoCreateInstance() before trying to use the pointer.

// check the return code
if (hr == REGDB_E_CLASSNOTREG)
{
    // try CoLoadLibrary...
    HINSTANCE hInstance = CoLoadLibrary([path to your DLL], FALSE);
    if (hInstance != NULL)
    {
        typedef HRESULT (__stdcall *pDllGetClassObject)(REFCLSID rclsid, REFIID riid, PVOID* ppv);
			
        pDllGetClassObject GetClassObject = (pDllGetClassObject)GetProcAddress(hInstance, "DllGetClassObject");
        if (GetClassObject != NULL)
        {
            IClassFactory*	pIFactory;

            hr = GetClassObject(CLSID_CGeneric, IID_IClassFactory, (PVOID*)&pIFactory);

            if (SUCCEEDED(hr))
            {
                hr = pIFactory->CreateInstance(NULL, IID_IGeneric, (PVOID*)&pGeneric);
                pIFactory->Release();
            }
        }
    }
}
if (SUCCEEDED(hr))
{
    // use the COM object as required
}