well interestingly enough, I made a quick test app so I could show you
the problem, but it appears my test app works just fine. Also note
that the casting error I was getting before was at runtime not when
compiling.

I had to use my ugly method of testing for inhertience because
IsSubclass and IsAssignableFrom were returning false for me.
Interestingly IsAssignableFrom returns true if my class Action is NOT
abstract. Clearly I'm missing something about the workings of these
methods.

I'll have to start changing my test app so that it's closer and closer
to the real thing and see when it breaks. Here is the test app and if
you have any thoughts let me know. Thanks for getting me to do the
test app... at least I know it's possible now with this approch.

Thanks,
Dan

*******************************************************************

DynamicLoader.GetClassesByClassName<Node>(Directory.GetCurrentDirectory()
+ @"\PluginTester.dll", null);

********************************************************************

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Reflection;

namespace PluginTester
{
   public abstract class Node
   {
       public abstract string NodeID { get; }
   }

   public abstract class Action : Node
   {
       //public abstract string NodeID { get; }
       public abstract string ActionID { get; }

   }

   public class MyAction : Action
   {
       public override string NodeID
       {
           get
           {
               return "MyAction";
           }
       }
       public override string ActionID
       {
           get { return "MyActionID"; }
       }
   }

   public class DynamicLoader
   {
       public static List<T> GetClassesByClassName<T>(string
fileName, object[] classParams) where T : class
       {
           List<T> ret = new List<T>();

           Assembly assembly = Assembly.LoadFrom(fileName);
           foreach (Type curType in assembly.GetTypes())
           {

               if (InheritsFrom(curType, typeof(T)) &&
curType.IsAbstract == false)
               {
                   if (classParams == null)
                   {
                       ret.Add((T)Activator.CreateInstance(curType));
                   }
                   else
                   {
                       ret.Add((T)Activator.CreateInstance(curType,
classParams));
                   }
               }
           }

           return ret;
       }

       private static bool InheritsFrom(Type curType, Type
targetType)
       {
           bool ret = false;

           while (curType.FullName != "System.Object")
           {
               if (curType.FullName == targetType.FullName)
               {
                   ret = true;
                   break;
               }
               else
               {
                   curType = curType.BaseType;
               }
           }

           return ret;
       }

   }

}