在旧的MFC / Win32 DLL中实现CLR并将DLL托管到MFC / Win32应用程序中

Question

I have an old MFC application which I currently import an old MFC/Win32 DLL into.

In this old DLL, I have been tasked with writing a bunch of Multi-Threaded code which I was planning on writing using the .NET framework (hence needing the CLR).

I've made cracks at this before, and even if I can get the project to compile properly with the CLR, I find that as soon as I try to use the DLL's user interface (written in MFC) after loading the DLL into the MFC/Win32 application, the application will crash pointing to problems with the user interface.

This DLL has always worked without the CLR, so I know that it is not broken.

What is the best way of implementing the CLR in my project, even if it is only for one class?

EDIT : I currently can get the code to build with the CLR only on the one class I need it in, but the application I load the DLL into still crashes upon trying to load the user interface contained in the DLL.

EDIT2 : I have figured out that it is failing an assertion on afxCurrentResourceHandle in afxwin1.inl . After doing more reading, I have a feeling that this has to do with MFC being in a "shared DLL" instead of "static DLL." Is there a workaround for this assertion?

_AFXWIN_INLINE HINSTANCE AFXAPI AfxGetResourceHandle()
    { ASSERT(afxCurrentResourceHandle != NULL);
        return afxCurrentResourceHandle; }

EDIT3 : I have made progress, but am still failing assertions! Apparently before you create the objects of the pages within the user interface, you must use the AFX_MANAGE_STATE macro to have afxCurrentResourceHandle be defined!

Here's an example of what I mean:

CPropertySheet Sheet("Config"); //Assume this is defined
AFX_MANAGE_STATE(AfxGetStaticModuleStatus());

CConfigPage ConfigPage;
CTestPage TestPage;

//Now I am failing an assertion when trying to run the following code
if (Sheet.DoModal() == ID_OK)
{
    //Do stuff...
}

The assertion currently failing now is:

CObject* AFX_CDECL AfxStaticDownCast(CRunTimeClass* pClass, CObject* pObject)
{
    ASSERT(pObject == NULL || pObject->IsKindOf(pClass));
    return pObject
}

pObject certainly isn't null: pObject: 0x043fd4fc {CWnd hWnd=0x002c0abe}

Answer 1

Combining MFC and .NET/CLR is unlikely to work, unless you can recompile the old MFC application with CLR support . Even then, I would strongly discourage it; the two frameworks are not intended to be used simultaneously. Keep in mind that you can only use one GUI thread even if you don't use MFC.

A better solution would be to use the standard MFC threading mechanisms. It's really not hard; just make a new class with a member function like this:

static UINT Go(LPVOID pParam);

Then call AfxBeginThread(Go, this) from somewhere else in your class. Recast pParam to pointer to your class and then start calling functions on it. You don't have to use anything fancy to make that strategy work in MFC, and you've got all the standard Win32/MFC/C++ resources available. Tell me what you need from .NET and I bet I can find a way to do the same thing in C++ or through COM.