Using Java libraries in a C# app with IKVM

I'm sure all us C# guys, at some point or another, have looked 'over the fence' with envy at all those juicy Java libraries. In my case, recently I needed to export and import some Excel files, and found that there aren't really any good C# libraries for it. So i'd heard of IKVM and thought, why not give it a try? And it worked, really simply I might add! So here are the steps. Note that they're pretty generic across most libraries, but in my case this is all relating to the JXL library. Firstly download IKVM. I grabbed the ikvmbin-0.40.0.1.zip file. Then grab your JAR file from the library you want to use. Copy it into the ikvm\bin folder, and from the command prompt, do this: ikvmc.exe my-jar-file.jar -target:library This will (hopefully) produce a my-jar-file.dll file. This is your .Net compiled version of the library. To use this new library, you'll want to copy it into your project and add it as a reference to your .net application, and do the same with some of the dll's from the IKVM\bin folder. I needed the following dll's for JXL, but you may need more or less, depending on what subset of the java standard library your library uses: IKVM.OpenJDK.Core.dll IKVM.OpenJDK.Text.dll IKVM.OpenJDK.Util.dll IKVM.Runtime.dll Then, in my code, you can call the library from C#, just as if it was a .Net library. See the example for JXL below:

using System;
using jxl;
using jxl.write;

namespace JxlFromCSharp
{
  class Program
  {
    static void Main(string[] args)
    {
      WritableWorkbook book =
        Workbook.createWorkbook(new java.io.File("new.xls"));
      WritableSheet sheet = book.createSheet("First Sheet", 0);
      Label lbl = new Label(0, 2, "My Label");
      sheet.addCell(lbl);
      book.write();
      book.close();
    }
  }
}

As an aside, i've since found a really good native .Net excel library (also it's open source): http://npoi.codeplex.com/

Thanks for reading! And if you want to get in touch, I'd love to hear from you: chris.hulbert at gmail.

Chris Hulbert

(Comp Sci, Hons - UTS)

Software Developer (Freelancer / Contractor) in Australia.

I have worked at places such as Google, Cochlear, Assembly Payments, News Corp, Fox Sports, NineMSN, FetchTV, Coles, Woolworths, Trust Bank, and Westpac, among others. If you're looking for help developing an iOS app, drop me a line!

Get in touch:
[email protected]
github.com/chrishulbert
linkedin

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