Jialiang Ge has just finished a summary of solutions to invoke .NET assembly from native C++ code.
Solution 1. Use a C++/CLI wrapperSolution 2. Host CLRSolution 3. Convert .NET assembly to a COM server, and call it from C++ through .NET-COM interop
The detailed and working code samples are attached to the above article. If you have any comments or questions about the code samples, please do contact firstname.lastname@example.org. Your feedback is very important to the work.