C# dll that can be pinvoked?

Question

Question: Is it possible to write a C# dll that can be pinvoked ?

I want to write a replacement library for the WinAPI calls WritePrivateProfileString etc. for reading and writing ini files.

Is it possible to export a function, e.g. 'WritePrivateProfileString', implemented in C# so one can pinvoke the dll with DllImport ?

I want to replace the native dll with a managed dll, so the managed dll gets called by the pinvoke call (instead of the native dll, when the managed dll is in the bin directory).

Answer 1

Contrary to popular belief, this is possible. (note that you'll need to modify the calling application to import from your DLL)
See here.

However, in your case, it's not necessarily a good idea.
Why don't you change the extern declarations to normal methods that call your replacements?

Answer 2

This is not easy, but it can be done with the use of a few “hacks”

However COM may be a better option for you, as it is easy to export a com object from C# and to use com objects from VB6. Then change the extern declarations to normal methods that call you’re your com objects.

Answer 3

Try using Mono Cecil to change the third-party program's extern methods to methods that call your DLL (without P/Invoke).

Reflector will help here.