Search an assembly for all child types?

I'd like to find all the types inheriting from a base/interface. Anyone have a good method to do this? Ideas?

I know this is a strange request but its something I'm playing with none-the-less.

From stackoverflow

• Use Assembly.GetTypes() to get all the types, and Type.IsAssignableFrom() to check for inheritance. Let me know if you need code - and also whether or not you're using .NET 3.5. (A lot of reflection tasks like this are simpler with LINQ to Objects.)

  EDIT: As requested, here's an example - it finds everything in mscorlib which implements IEnumerable. Note that life is somewhat harder when the base type is generic...

  using System;
  using System.Collections;
  using System.Linq;
  using System.Reflection;
  
  class Test
  {
      static void Main()
      {
          Assembly assembly = typeof(string).Assembly;
          Type target = typeof(IEnumerable);        
          var types = assembly.GetTypes()
                              .Where(type => target.IsAssignableFrom(type));
  
          foreach (Type type in types)
          {
              Console.WriteLine(type.Name);
          }
      }
  }
  

  TheDeeno : Jon Skeet is everywhere! haha, thanks.

  Aaron Wagner : I'd love to see that code since I can't get Type.IsAssignableFrom() to work the way I'm understanding it. I'm on 3.5 sp1. Thanks!

  Aaron Wagner : Thank you Jon Skeet!

• var a = Assembly.Load("My.Assembly");
  foreach (var t in a.GetTypes().Where(t => t is IMyInterface))
  {
      // there you have it
  }
  

  Jon Skeet : No, that won't work - "is" checks whether an *object* implements an interface, and the instance of "Type" doesn't implement IMyInterface. That's why I suggested using Type.IsAssignableFrom.

• Or for subclasses of a base class:

  var a = Assembly.Load("My.Assembly");
  foreach (var t in a.GetTypes().Where(t => t.IsSubClassOf(typeof(MyType)))
  {
      // there you have it
  }