Porting (unmanaged) C++ to C# vs. using the C++ as a DLL in a C# application

Question

I have a code library written in plain old C++ (no .NET/managed code) and I'm porting the application that uses this code to C#. I'm faced with two options:

1. Rewrite the C++ code in C# to achieve the same functionality;
2. Compile the C++ as a DLL and use it as a library in the C# application.

I'm relatively new to C# and am pretty unfamiliar with the implications of using an unmanaged code library in a C# app (or if there even are any). The code itself is moderate in size; it will likely take only a few days to rewrite in C#, but my thought is that leaving the code as a it is would allow me to use it in other applications as well (and to compile it on UNIX, etc).

What sort of things should I be aware of when making this decision? Are there any major drawbacks or gotchas to using the DLL in the C# application?

Answer 1

I would make a wrapper library using C++/CLI to expose the library to C#. This can leave your library unchanged, and just wrap it for use from .NET, providing the best of both options.