Question

Is it possible to determine the interfaces that can be used to cast a MarshalByRefObject object?

How does the cast operator work with MarshalByRefObject objects? Does it call the CreateObjRef method?

Thanks,
Massimo

Answer 1

Here’s a workaround that can be used to retrieve the list of interfaces.

Define a public interface IDescriptor

public interface IDescriptor
{
   List<string> GetInterfaces();
}

Define a base class that implements the interface:

public class BaseMasrhalByRefObject : MasrhalByRefObject, IDescriptor
{
   public BaseMasrhalByRefObject() : base() {}

   public List<string> GetInterfaces()
   {
      List<string> types = new List<string>();
      foreach(Type i in GetType().GetInterfaces())
      {
         types.Add(i.AssemblyQualifiedName);
      }
      return types;
   }
}

Than use the BaseMasrhalByRefObject instead of MasrhalByRefObject to define a service object:

public class MyServiceObject : BaseMasrhalByRefObject, MyInterface1, MyInterface2, ...
{
      // Add logic method
}

In AppDomain A create the reference object of MyServiceObject.
In AppDomain B get the proxy of the remote object. The proxy can be cast to IDescriptor:

public List<Type> GetInterfaces(MasrhalByRefObject proxy)
{
   List<Type> types = new List<Type>();
   IDescriptor des = proxy as IDescriptor;
   if (des != null)
   {
      foreach(string t in des.GetInterfaces()) // this is a remote call
      {
         types.Add(Type.GetType(t);
      }
   }
   return types;
}