EEFileLoadException when using C# classes in C++(win32 app)

Question

For deployment reasons, I am trying to use IJW to wrap a C# assembly in C++ instead of using a COM Callable Wrapper.

I've done it on other projects, but on this one, I am getting an EEFileLoadException. Any help would be appreciated!

Managed C++ wrapper code (this is in a DLL):

extern "C" __declspec(dllexport) IMyObject* CreateMyObject(void)
{
    //this class references c# in the constructor
    return new CMyWrapper( );
}

extern "C" __declspec(dllexport)  void DeleteMyObject(IMyObject* pConfigFile)
{
    delete pConfigFile;
}

extern "C" __declspec(dllexport) void TestFunction(void)
{
    ::MessageBox(NULL, _T("My Message Box"), _T("Test"), MB_OK);
}

Test Code (this is an EXE):

typedef void* (*CreateObjectPtr)();
typedef void (*TestFunctionPtr)();

int _tmain testwrapper(int argc, TCHAR* argv[], TCHAR* envp[])
{
    HMODULE hModule = ::LoadLibrary(_T("MyWrapper"));
    _ASSERT(hModule != NULL);

    PVOID pFunc1 = ::GetProcAddress(hModule, "TestFunction");
    _ASSERT(pFunc1 != NULL);
    TestFunctionPtr pTest = (TestFunctionPtr)pFunc1;

    PVOID pFunc2 = ::GetProcAddress(hModule, "CreateMyObject");
    _ASSERT(pFunc2 != NULL);
    CreateObjectPtr pCreateObjectFunc = (CreateObjectPtr)pFunc2;

    (*pTest)();  //this successfully pops up a message box
    (*pCreateObjectFunc)();  //this tosses an EEFileLoadException

    return 0;
}

For what it's worth, the Event Log reports the following: .NET Runtime version 2.0.50727.143 - Fatal Execution Engine Error (79F97075) (80131506)

Unfortunately, Microsoft has no information on that error.

Answer 1

The first issue is to make sure the Debugger type is set to mixed. Then you get useful exceptions.

Answer 2

For you native application consuming the mixed mode dll (Your EXE), change the **"Debugger Type" to "Mixed" mode. (Go to Project Properties -> Configuration Properties -> Debugging)

There are some other points (which might not be relevant to you) but in my experience they could cause issues. - On windows 8 (with tighter security) please try launching your VS as admin. - Make sure that for x86 configuration you are using x86 binaries. - Watch for StrongName verification, if your C# assemblies which you are consuming in Managed C++ as signed, please consider signing the mixed mode dll too.

Hope this would help.