C# in-process compiler

CSharpInProcessCompiler

using System;
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Text;
using Microsoft.CSharp;

namespace ActiveMesa.R2P.Infrastructure
{
  internal class CSharpInProcessCompiler
  {
    internal Assembly Compile(string sourceCode, string compilerVersion = "v4.0")
    {
      CompilerParameters ps = PrepareCompilerParameters();

      var po = new Dictionary<string, string>
        {
          {"CompilerVersion", compilerVersion}
        };
      var p = new CSharpCodeProvider(po);
      var results = p.CompileAssemblyFromSource(ps, new[] {sourceCode});

      if (results.Errors.HasErrors)
      {
        var sb = new StringBuilder();
        foreach (var e in results.Errors)
          sb.AppendLine(e.ToString());
        throw new Exception(sb.ToString());
      }

      return results.CompiledAssembly;
    }

    internal Type CompileAndGetType(string sourceCode, string compilerVersion = "v4.0")
    {
      var ass = Compile(sourceCode, compilerVersion);
      var types = ass.GetTypes();
      if (types == null || types.Length == 0)
        throw new Exception("Compiled assembly produced no types");
      else
        return types[0];
    }

    internal object CompileAndInstantiate(string sourceCode, string compilerVersion = "v4.0")
    {
      var mainType = CompileAndGetType(sourceCode, compilerVersion);
      return Activator.CreateInstance(mainType);
    }

    private CompilerParameters PrepareCompilerParameters()
    {
      var ps = new CompilerParameters {GenerateInMemory = true, GenerateExecutable = false};

      // add everything in this AppDomain
      foreach (var reference in AppDomain.CurrentDomain.GetAssemblies())
      {
        try
        {
          ps.ReferencedAssemblies.Add(reference.Location);
        }
        catch (Exception ex)
        {
          string s = "Cannot add assembly " + reference.FullName + " as reference.";
          Debug.WriteLine(s);
        }
      }

      return ps;
    }
  }
}