How to use C# function in Java using JNA lib

Question

I\'ve spent many hours trying to use a C# function inside my Java Application but had no success... I wrote the following lib in C#:

public class Converter
{         


        

Answer 1

As said by technomage:

JNA can load from DLLs that use C linkage. A C# class does not by default support any kind of C linkage. C++ supports C linkage with the extern "C" notation.

This article shows a way to make C# DLLs methods callable like C-style DLL, unfortunately it's a quite complex.

Answer 2

This Nugget is super easy to use and works perfectly. https://www.nuget.org/packages/UnmanagedExports

You need Visual Studio 2012 (express). Once installed, just add [RGiesecke.DllExport.DllExport] before any static function you want to export. That's it!

Example:

C#

[RGiesecke.DllExport.DllExport]
public static int YourFunction(string data)
{
     /*Your code here*/
     return 1;
}

Java

Add the import at the top:

   import com.sun.jna.Native;

Add the interface in your class. Its your C# function name preceded by the letter "I":

  public interface IYourFunction extends com.sun.jna.Library
    {
       public int YourFunction(String tStr);
    };

Call your DLL where you need it in your class:

IYourFunction iYourFunction = (IYourFunction )Native.loadLibrary("full or relative path to DLL withouth the .dll extention", IYourFunction.class);//call JNA
        System.out.println("Returned: " + IYourFunction.YourFunction("some parameter"));