Using C# classes in Xojo

Getting Started
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I’ve been able to get this working using the Unmanaged Exports – which is HUGE for folks who need to create DLL’s and want to take advantage of .NET and the whole C# ecosystem.

This avoids the whole COM-Visible and COM-interop nightmare which can slow down a project, and also complicate things.

“Unmanaged Exports” a C# class library package by Robert Giesecke.

No more ActiveX wrapper! Excellent stuff!

Here’s what you do:

  1. Get the NuGet packages for VS 2010 or better, install them in your VS 2012 system.
  2. Create a VS C# Class Library Project
  3. When you create a method make sure its “static”, and that you decorate it with [DllExport]
  4. Compile the project, place the DLL in the runtime location of your Xojo project or make sure the Declare has a direct path
    to that DLL
  5. Voila! .NET DLL access from Xojo… no ActiveX wrapper, no COM-Interop.

Below is a code snippet.

C#

using System;
using RGiesecke.DllExport;
using System.Runtime.InteropServices;

public class TestExport
{
 
    [DllExport]
    public static int Test(string TestString)
    {
        return TestString;
    }
}
Declare Function Test lib "TestExport.dll" (msg as CString) AS String
 
 Msg ( Test ("Hello, .NET Class Library DLL!"))