Question

I have a class like this:

public class Data
{
    public string Name { get; set; }
    public int Size { get; set; }
    public string Value { get; set; }

    [NonSerialized] public byte[] Bytes;
}

When a List<Data> hits the serialization method below, it occasionally dies with

InvalidOperationException “This
XmlWriter does not support base64
encoded data.”

As you can see, I am not directly encoding anything, just using the default serialization mechanism.

private static XDocument Serialize<T>( T source )
{
    var target = new XDocument( );
    var s = new XmlSerializer( typeof( T ) );
    using( XmlWriter writer = target.CreateWriter( ) )
    {
        s.Serialize( writer, source );
    }
    return target;
}

The data will have Name properties that are English words separated by underscores. The Value property will by similar except with added math operators or numbers (they are mathematical expressions).

Does anyone know what is causing it and how I can correct it?

Answer 1

Use [XmlIgnore] instead of [NonSerialized]. The latter is for the SOAP and binary formatters, according to MSDN:

When using the BinaryFormatter or
SoapFormatter classes to serialize an
object, use the NonSerializedAttribute
attribute to prevent a field from
being serialized. For example, you can
use this attribute to prevent the
serialization of sensitive data.

The target objects for the
NonSerializedAttribute attribute are
public and private fields of a
serializable class. By default,
classes are not serializable unless
they are marked with
SerializableAttribute. During the
serialization process all the public
and private fields of a class are
serialized by default. Fields marked
with NonSerializedAttribute are
excluded during serialization. If you
are using the XmlSerializer class to
serialize an object, use the
XmlIgnoreAttribute class to get the
same functionality.

Mind you, I’m surprised your original code even compiles – when I try it, it says that [NonSerialized] can only be applied to fields…