You can use a normal native dll from C# using P/Invoke. Export your C++ functions using
extern "C"
to prevent C++ name mangling, then import them in your C# project like this:
[DllImport( "user32.dll" )]
public static extern IntPtr SendMessage(
IntPtr hWnd,
UInt32 msg,
IntPtr wParam,
IntPtr lParam );
There's plenty of info on P/Invoke on the net. This site will give you plenty of examples:
http://www.pinvoke.net/[
^]
Nick