Why is it whenever I use System.Web.Hosting.ApplicationHost.CreateApplicationHost it always returns System.IO.FileNotFoundException?

I'm trying to host asp.net application and asp web services without IIS. I found the cassini web project and other tutorial around the net. All of them are using the CreateApplicationHost from System.Web.Hosting.ApplicationHost namespace. I copied some code from those project and build it properly but whenever I tried to run it on debug I always get the file not found error. I think it is caused by the Virtual Directory path but don't know how to fix it.

public class MySimpleHost : MarshalByRefObject
    {
        public void ProcessRequest(string page, string query, TextWriter tw)
        {
            SimpleWorkerRequest swr = 
                new SimpleWorkerRequest(page, query, tw);
            HttpRuntime.ProcessRequest(swr);
        }
    }
 
 
namespace SimpleHost
{
    class Program
    {
        static void Main(string[] args)
        {
            string dir = System.IO.Directory.GetCurrentDirectory();
 
            MySimpleHost msh = (MySimpleHost)ApplicationHost.CreateApplicationHost(
                typeof(MySimpleHost), "/", dir);
         }
    }

Select allOpen in new window