using System;

using System.Linq;

using System.IO;

using System.Reflection;

using Microsoft.CodeAnalysis;

using Microsoft.CodeAnalysis.CSharp;

using Newtonsoft.Json.Linq;

​

public class Program

{

    public static void Main(string[] args)

    {

        var j = new JObject(); // ensure assembly is available

        Example1();

    }

​

    public static void Example1()

    {

        var assemblyName = "UserScript";

        var code = @"namespace UserScript { 

                      using Newtonsoft.Json;

                      using TagLib;

                      public class RunScript {

                       public static string Eval() {

                        TagLib.File tfile = default;

                        return JsonConvert.SerializeObject(new int[] {1,2,3,4});

                       }

                      }

                    }";

​

        SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(code);

        //Load project libraries

        var references = AppDomain.CurrentDomain

            .GetAssemblies()

            .Where(a => !a.IsDynamic)

            .Select(a => a.Location)

            .Where(s => !string.IsNullOrEmpty(s))

            .Where(s => !s.Contains("xunit"))

            .Select(s => MetadataReference.CreateFromFile(s))

            .ToList()

            ;

​

        CSharpCompilation compilation = CSharpCompilation.Create(

            assemblyName,

            new[] { syntaxTree },

            references, //<-- you're missing this

            new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));

​

        using (var memoryStream = new MemoryStream())

        {

            var result = compilation.Emit(memoryStream);

​

            if (result.Success)

            {

                memoryStream.Seek(0, SeekOrigin.Begin);

                Assembly assembly = Assembly.Load(memoryStream.ToArray());

​

                var testClassType = assembly.GetType("UserScript.RunScript");

                var invokeResult = (string)testClassType.GetMethod("Eval").Invoke(null, null);

                Console.WriteLine(invokeResult);

            }

            else

            {

                Console.WriteLine("Failed to compile");

                foreach (var diag in result.Diagnostics)

                    Console.WriteLine(diag);

            }

        }

    }

}