How to work with an interface dynamically loaded from an assembly and invoke its members

I have got some code to load an assembly and get all types, which implement a certain interface, like this (assume asm is a valid and loaded assembly).

var results = from type in asm.GetTypes()
  where typeof(IServiceJob).IsAssignableFrom(type)
  select type;

Now I'm stuck: I need to create instances of these objects and invoke methods and properties on the object. And I need to store the references to the created objects in an array for later usage.

From stackoverflow

• Oh wow - I only blogged about this a few days ago. Here's my method to return instances of all the types that implement a given interface:

  private static IEnumerable<T> InstancesOf<T>() where T : class
  {
      var type = typeof(T);
      return from t in type.Assembly.GetExportedTypes()
             where t.IsClass
                 && type.IsAssignableFrom(t)
                 && t.GetConstructor(new Type[0]) != null
             select (T)Activator.CreateInstance(t);
  }
  

  If you refactor this to accept an assembly parameter rather than using the interface's assembly, it becomes flexible enough to suit your need.

  Chad Grant : That's some crazy LINQ there man. ;)

  towps : @Matt Hamilton: is it possible then to invoke a constructor in such a way of there is no default empty constructor?

  Matt Hamilton : Activator.CreateInstance has an overload which can accept an array of objects that are passed to the ctor of the class you're instantiating, but I don't think there's any way you could use that within a single query like the one I've posted here.

• You can create an instance of a type with the Activator.CreateInstance method:-

  IServiceJob x = Activator.CreateInstance(type);
  

  So your code becomes:-

  IServiceJob[] results = (from type in asm.GetTypes()
    where typeof(IServiceJob).IsAssignableFrom(type)
    select (IServiceJob)Activator.CreateInstance(type)).ToArray();
  

  (Note change var to IServiceJob[] to make it clear what is being created).

  Matt Hamilton : Keep in mind that if the implementing type doesn't have a default ctor, this code will throw a MethodMissingException. Hence the check in my query.

  towps : @Matt Hamilton: is it possible then to invoke a constructor in such a way of there is no default empty constructor?