I have some existing C++ classes (including methods and #define constants, as well as a couple of extra C-style functions) that I would like to use in a new C# application. What's the best way to do this? I'd rather have everything linked into the one exe, so no DLLs if possible, but just linking into class libraries.
What's the best way to do this? Is it fairly straight forward, or am I better off porting my original code to C#?
As far as I know, your best bet may be to convert your code to C++/CLI, if you want to put them into your project/solution.
If you want to just call those C++ code as an external library, you can use P/Invoke. But my experience with it has been painful. Other than fairly trivial stuff, it has a steep learning curve. But there are really knowledgeable people regarding that subject on SO (like Hans Passant) that can help you.
Of course, you always have the option to rewrite everything in C#.
Managed C++ should be the best option. As, You can mix native and managed code within a single .dll, which is called a mixed-mode assembly. This is done by compiling some of the C++ files using /clr and some using normal C++
You should be able to use PInvoke/DLLIMPORT to call any function in your C, C++.
Update 1:
I had a success in calling C function, but not C++ class/methods.
You would have to use Managed C++ to do this. This article should help..
Update 2: Rearranging as suggested by David.
For purely C style implementation you could use P/Invoke. Reference you could use LibGit2Sharp project. Which consume a native C.exe in C#. Here are the DllImport Calls Native Methods
Note: Here, you would have to ship the exe, it cannot be compiled into any other .Net assemblies.
__declspec(dllexport) on the c++ method.. msdn.microsoft.com/en-us/library/ms235636(v=vs.100).aspx_declspec only then C# can access it using P/Invoke..