Adding an unmanaged C++ dll to a managed C++ dll

Question

I am trying to add an unmanaged C++ dll to a managed (CLI) C++ dll project. When I click the "class wizard," I get a "MFC classes can only be added to MFC projects" error message. I am not using MFC, to the best of my knowledge (Use of MFC is blank under my unmanaged dll's project page). Is there another way to add an unmanaged dll to my managed dll's project?

For anyone who is interested, I've thrown the rared solution up on my DropBox account: https://dl.dropbox.com/u/98752313/CplusplusArrayTest.rar

I realize there are far too many settings that could be wrong for me to simply copy and paste everything into the available space.

There are three projects within this solution. CplusplusArray (should be complete, it's the unmanaged .dll), ManagedCpluspplusArray (need to add the unmanaged dll, and modify a few things, it's the managed .dll), and a C# test program (not written yet, will hopefully talk to the unmanaged dll through the managed dll).

The whole goal of this project, if you are wondering, is to give C# the ability to use arrays with longs as the indexers. If you've used any amount of .Net before, you may have run into the Int32/Uint32 limit on the size of objects in the CLR. I am hoping to get around that by implementing the array in C++ land, then modifying / compiling some Mono Collections.Generics classes against it, thus giving us some breathing room. The reason I am doing C# -> C++/CLI -> C++ is so that, according to my research, we can use object oriented code with it; the DllImport stuff works fine for C-like functions only, and I want to preserve OOP, rather than modify things to work C-like. Since arrays are the building blocks of the List / etc. classes, from what I can tell, of the Collections namespace, getting just them to function in 64-bit land will give us everything else.

Answer 1

You need to add a new project, not a new class. Once you "Add Project", you will be asked what type of project you want to add, and a plain C++ DLL will be one of your options.

Once you have both projects in your solution (a C++/CLI DLL project, and a C++ DLL project), you can go to the workspace dependencies and indicate that one of them depends on the other.

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Additional notes:

The Class Wizard is all about adding MFC classes. Because you're not interested in adding MFC classes, this is not the right tool to use.

When I have written a C++/CLI DLL that utilized a native C++ DLL, I needed to add instructions to link to the C++ DLL's import library. This was configured in:
"Project Properties > Configuration Properties > Linker > Input > Additional Dependencies"

The workspace dependencies guarantee that the unmanaged library is built first, and that if the unmanaged library is updated, the managed library will be recompiled or relinked if needed.