Hello there,

I have a problem with my DirectX11/C++-Engine. I started writing it as an independent project, with a main.cpp and all that. When it had grown bigger and I started to need it for multiple projects, I came up with the idea of putting it into a library. I had to choose between .lib and .dll, and since I am not experienced with either of these, I went for the .lib, since from what I read, exporting it as .dll would require me to rewrite ALL classes that are supposed to be accessed from outwards.

Now I want to create a worldbuilder from it, and for the interface I used .NET. C++ at frist, but I noticed that it was dropped from Visual Studio since 2012 (it worked out fine though). I was told to use C# instead, but now I can't figure how to include my C++ lib into a C# project, and how to call functions from it - they require e.g a HWND handle, which can't be used in C#, since it is declared "unsafe".

What would you suggest me to do? Just carry on with the old C++.Net, or find a way of using it in C#? And should I stick with the .lib or rewrite my code so it can be used in a .dll file?

Thanks for your concern and best whishes!

-gnomgrol

This might not be useful in all cases, but I have a game engine written in C++ and I wanted an editor in C# from the very beginning.

== My Approach ==

In my case, I use a library called SWIG to generate C# wrappers around C++ classes that I want to expose to an editor. It might take a long time to tweak the ".i" files so that the C# output is exactly what you want.

So, the typical setup is:

- Special build for Editor. First we run SWIG to generate C# wrappers and a master .cxx file that contains the DLL invoke receiver functions.

- Engine compiles to a DLL with regular C++ files and the .cxx file.

- Link in your DLL into the C# project as a reference.

- File link your C# files into the Editor C# project.

You'll need to keep them somewhat synchronized when you make changes to your C++ api. You can write many extensions on top of the C++ classes to bring in really nice C# functionality like reflection, properties etc.

== Second Approach ==

I did this in the past but it is Windows ONLY.

- A version of your C++ editor that properly compiles into a C++/CLI DLL.

- Use the DLL as a reference in your pure C# editor project.

Writing CLI compatible C++ code requires a lot of consideration though.

Hope this helps,

Mitesh

Hey Mitesh, thanks for your answer!

Since I am targeting windows-only anyways, I would like to go with your second suggestion.

My c++-files compile fine with the /cli:pure option checked - I needed that for the c++.NET editor anyways. Does that mean it is already fully CLI compatible?

I can just call my C++-classes from a dll in my C# project as soon as I linked it?

Is rewriting my .lib to a .dll a lot of work? I got around 200 classes, and having to change all of them would take quite some time. Is there some kind of trick to it?

As far as I know, the dll is executable code while a .lib is compiled code which is yet to be linked to any executable.

You'll need to adjust your Visual Studio project, or just create a new one for this DLL build.

I did this many years ago, but what I remember with C++/CLI dlls is that they work like any other .NET reference. Which means they are usable with any language supported by the common language system. C#, F#, VisualBasic - you name it.

I'm a bit rusty so other members who have done this recently should share this easy bit of info.