System.Refelection.Assembly.CreateInstance broken in .NET 4.0

We upgraded from .NET 3.5 to .NET 4.0 and now System.Refelection.Assembly.CreateInstance does not appear to be working. Has anyone else had this problem? Is there a way to fix it? Below is an example of how we are loading the asembly. It returns a null value. No exception. It's a .NET Assembly registered in the GAC. It is not a COM object.

Assembly assembly = Assembly.LoadWithPartialName("AssemblyName");
object instance = assembly.CreateInstance("Namespace.Class",
                        false,
                        BindingFlags.CreateInstance,
                        null,
                        null, null, null);

I narrowed down the cause of the problem. My class A that I am trying to create inherits from class B. Class B is defined as public abstract class B. Class B contains most of the logic with one abstract method that class A defines. Similarly I have another class C that inherits from Class B that has a different开发者_高级运维 definition for the method. Basically refactoring to share common logic. This worked in .NET 3.5 but in .NET 4.0 I finally narrowed down the exception to be "{"Cannot create an abstract class."}".

public abstract class A
{
  public string InvokeUI() 
  {
    //some logic
    DisplayUI();
  }

  protected abstract void DisplayUI();
}

public class B : A
{
  protected override DisplayUI()
  {
    Some logic;
  }
}

---

With the Activator it works fine with .net Framework 4.0 compiled with the following platforms (x86/x64/Any CPU):

using System.Reflection;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var ass = Assembly.Load("ConsoleApplication1");
            var type = ass.GetType("ConsoleApplication1.Test");
            var obj = Activator.CreateInstance(type);
            Console.ReadLine();


        }
    }

    public class Test    {        }
}

---

You have to use fusion.dll library to read the GAC. Once you find the “Full Assembly Name” you can use Reflection.[Assembly].Load() instead of Reflection.[Assembly].LoadWithPartialName(). There is the article I wrote that explains what needs to be done:

http://www.codeproject.com/Articles/485145/Late-Binding-to-NET-objects-in-NET-4-0