.net - Serialization exception in remoting C# -

i've been trying lot before writing question couldn't find answer problem.

i'm making remoting program, it's store, i've implemented .dll, server , client, , ok except fact have big problem related serialization, little summary code.

[serializable] public class almacen {     int nusuarios_on, nusuarios_reg;     bool server_on;     arraylist clientes_activos;     arraylist clientes_registrados;     arraylist productos_almacen;}  [serializable] public class cliente {     protected int id;     protected string usuario, dni;     private string contraseña;     pedido pedido;}  [serializable] public class pedido {     arraylist productos;     bool confirmado;     int preciototal;}   [serializable] public class producto {     private string nombre;     private int codigo, precio, unidades, stock; //stock solo lo usamos en el almacen, y unidades solo en pedido.} 

then, have .dll service, in have method 'pedido' object passed value in parameter, when method called.

public class servicioalmacen : marshalbyrefobject {     private almacen almacen;     .     .     .     public int añadirproductoalmacen(int id, producto p) {     if(id==1) {         if(!productorepetido(p)) {             almacen.getproductos_almacen().add(p);             console.writeline("añadido el producto {0} al almacen.", p.getcodigo());             return 0;         }         else {             console.writeline("intento de añadir un producto repetido.");             return -1;         }     }     else {         console.writeline("acceso denegado.");         return -2;     }       }     .     .       . } 

when method called in client side, serializationexception tells me servicealmacen.producto not tagged serialized. dont understand why exception because tagged every class serialized, idea? thanks.

pd: if need client or server code let me know , edit post.

you sholud make members seriliazed in producto class public members , add or check thread seriliaze private member workaround c# serialize private class member