[ServiceContract]
    public interface IP
    {
        [OperationContract]
        Stream get_o();
    }

public class P : IP
    {
        public Stream get_o()
        {
            MemoryStream stream = new MemoryStream();
            BinaryFormatter formatter = new BinaryFormatter();
            using (EntityModelContainer context = new EntityModelContainer())
            {
                formatter.Serialize(stream, context.t_O.ToArray());
                stream.Seek(0, SeekOrigin.Begin);
                return stream;
            }
        }
    }

using (PClient proxy = new PClient())
    {
        Stream stream = proxy.get_o();
        BinaryFormatter formatter = new BinaryFormatter();
        t_O[] oList = (t_O[])(formatter.Deserialize(stream));
        this.dataGridView.DataSource = oList;
    }

sealed class DeserializationBinder : SerializationBinder
    {
        public override Type BindToType(string assemblyName, string typeName)
        {
            Type typeToDeserialize = null;
            String currentAssembly = Assembly.GetExecutingAssembly().FullName;
            assemblyName = currentAssembly;
            typeToDeserialize = Type.GetType(String.Format("{0}, {1}", typeName, assemblyName));
            return typeToDeserialize;
        }
    }  

BinaryFormatter formatter = new BinaryFormatter()
    {
        Binder = new DeserializationBinder()
    };