C#

class MyEntity
{
   private int id; // key from db

   public int GetHashCode()
   {
      return id;
   }
}

class MyComposite
{
   private MyFirstEntity firstEntity;
   private MySecondEntity secondEntity;
   private MyThirdEntity thirdEntity;
   private MyFourthEntity fourthEntity;
}

double e1Hash = (firstEntity.GetHashCode() * Math.Pow(100,3));
double e2Hash = (secondEntity.GetHashCode() * Math.Pow(100,2));
double e3Hash = (thirdEntity.GetHashCode() * 100);
double e4Hash = fourthEntity.GetHashCode();
int hash = (int)((Math.Abs(e1Hash+e2Hash+e3Hash+e4Hash ))%int.MaxValue);

// The delegate
public delegate void MyDelegate();
// The remote (server) object
class RemoteObject : System.MarshalByRefObject
{
    // code...
    
    public event MyDelegate EvMyEvent;
}

// The client object
class MyClient
{
    // code...
    
    private void MyDelegateFunction()
    {
    }
    
    public MyClient()
    {
        RemoteObject oRO = null;
        // Get the remote object
        oRO.EvMyEvent += new MyDelegate(MyDelegateFunction); // Exception:
        /*
             An unhandled exception of
             type 'System.Runtime.Serialization.SerializationException' occurred in 
             mscorlib.dll
    
             Additional information: Serialization will not deserialize delegates 
             to non-public methods.
        */
    }
}