IKVM C# to Java Interop with Callback using IKVM

Question

I\'ve started using IKVM to translate Java libs into .NET CIL. I can successfully write a C# program that pulls in (inproc) a translated Java assembly as a reference and make ca

Answer 1

JaapM, I think CSharpLibrary in mj_'s solution is a transient class from third C# DLL project (cshardassembly.dll), that he compiles first and then shares between actual java and C# code. It doesn't matter what's in it, the idea is that both sides have a piece of code (class) known in advance. This is overkill, if I'm correct.

I know, it's a long time passed but I would like to post a short solution here that works for me, cuz I wasted too much time on it and IKVM documentation is very poor:

Java:

package what.ever.package;
import cli.System.Delegate;
import cli.System.Int32;
public class SomeJavaClass
{
    public static void setCallback(Delegate callback)
    {
        // I call delegate in static setter to keep example short, 
        // but you may save it and call later...
        Int32 result = (Int32)callback.DynamicInvoke("hello", "world");
        System.out.println("Callback returned [" + result + "]");
    }
}

Don't forget to convert mscorlib.dll into jar and attach it to your java project to support cli imports. build it and run ikvmc.exe on jar with -target:library parameter and add resulting DLL into C# project.

C#:

using what.ever.package
class Program
{
    // signature of delegate must match target function.
    public delegate Int32 TheDelegateItself(String a, String b);

    // callback that we pass into java.
    public static Int32 DelegateTarget(String a, String b)
    {
        Console.WriteLine("DelegateTarget Executed: [" + a + ", " + b + "]!");
        return 42;
    }

    static void Main(string[] args)
    {
        // again, static call to keep it short
        // but you may want a class instance in most cases.
        SomeJavaClass.setCallback(new TheDelegateItself(DelegateTarget));
    }
}

output:

DelegateTarget Executed: [hello, world]!
Callback returned [42]