exposing API to C++ dll from C#

Question

I have a plugin written for a C++ program (as a .dll). The interface this .dll relies on is something like the following:

class Platform
{
    virtual bool callSomeFunc() = 0;
    //etc.
}

The .dll provides the platform with an object through an extern "C" function. Pretty standard. The .dll can interact with the platform via an object of a class implementing the above interface. Pretty standard I guess.

Now we have a need to write the platform in C#. Ideally without rewriting the plugin because we have most of our code in plugin. Is there a way to go about this? (Something like passing a C# object for the Platform object the .dll expects?)

Answer 1

If you wish to implement an object in the C# code that the unmanaged code can use, then you can no longer use a C++ class. Only C++ code can create C++ classes. C# code cannot.

The obvious thing to do is to use COM for your interop. The C# code can both implement and consume COM objects.