Serializing / Deserializing Derived Class

I have a base class and another one derived from it. Suppose the base class has 20 members and has 5 members. Only the derived class is serializable.

After I create an instance, the derived class object has all 25 members. Now, how can I only serialize 5 members of a derived class? When I use "this" to serialize or deserialize, the entire class (all 25 members) is serialized and then deserialized.

Here is a code snippet (not complete):

// Base class definition.
public abstract class baseMyClass
{
// declaration of members
}

...

// Derived class definition.
[Serializable]
public sealed class MyDerivedClass : baseMyClass
{
// declaration of members
}

...

// Serializing the object.
StringWriter writer = new StringWriter();
XmlSerializer xs = new XmlSerializer(typeof(MyDerivedClass));
xs.Serialize(writer, this);

...

// Deserializing the object.
StringReader reader = new StringReader(System.Text.Encoding.UTF8.GetString(data));
XmlSerializer xs = new XmlSerializer(typeof(MyDerivedClass));
MyDerivedClass objMyDerivedClass = (MyDerivedClass)(xs.Deserialize(reader));

      

        
        
        
      

    

I couldn't find a similar example. If you know one, please point it to me.

Thanks for the help.