Override DefaultValue during XML Serialization

[Craig Schneider]

// Is there any way to override the XML Serialization of the following
SimpleClass
// to turn off the DefaultValue of a boolean? Sure, I can override
the DefaultValue from
// true to false, but that is not what I want/need. I really need to
just override the fact
// that the developer ever supplied a DefaultValue. Setting an
override DefaultValue of null
// or "new object()" errors. Any help would be appreciated.

using System;
using System.Collecti ons;
using System.Componen tModel;
using System.IO;
using System.Xml.Seri alization;

namespace XMLStub
{
/// <summary>A simple class to be XML Serialized.</summary>
public class SimpleClass
{
[DefaultValue(tr ue)]
public bool TheBool = true;

[DefaultValue("I nitialValue")]
public string TheString = "InitialVal ue";

public SimpleClass(boo l NewBool, string NewString)
{
TheBool = NewBool;
TheString = NewString;
}

public SimpleClass()
{
}
}

/// <summary>A simple class that holds a collection of
SimpleClass.</summary>
public class SimpleCollectio n : CollectionBase
{
public SimpleClass this[int Index]
{
get { return((SimpleC lass)List[Index]); }
}

public void Add(SimpleClass NewSimpleClass)
{
List.Add(NewSim pleClass);
}
}

class gMain
{
[STAThread]
static void Main(string[] args)
{
//SimpleClass InstanceToSeria lize = new SimpleClass();

SimpleCollectio n InstanceToSeria lize = new SimpleCollectio n();
InstanceToSeria lize.Add(new SimpleClass(tru e, "I am true"));
InstanceToSeria lize.Add(new SimpleClass(fal se, "I am false"));
InstanceToSeria lize.Add(new SimpleClass(tru e, "true #2"));
InstanceToSeria lize.Add(new SimpleClass(fal se, "false #2"));

// Serialize with the pre configured default values.
XmlSerializer Serializer = new
XmlSerializer(I nstanceToSerial ize.GetType());
StringWriter XMLStringWriter = new StringWriter();
Serializer.Seri alize(XMLString Writer, InstanceToSeria lize);
Console.WriteLi ne("\nWITHOUT Overrides: \n" +
XMLStringWriter .ToString());

// Attempt to serialize as if there were no default values set.
XmlAttributeOve rrides ExplicitOverrid es = new
XmlAttributeOve rrides();

// Setup the override default value for TheString.
XmlAttributes TheStringAttrib utes = new XmlAttributes() ;
TheStringAttrib utes.XmlDefault Value = "SOME TEXT THE STRING WILLL
NEVER CONTAIN";
ExplicitOverrid es.Add(typeof(S impleClass), "TheString" ,
TheStringAttrib utes);

// Setup the override default value for TheBool.
XmlAttributes TheBoolAttribut es = new XmlAttributes() ;
TheBoolAttribut es.XmlDefaultVa lue = false; // Works, but
only for a single instance, fails for an array or collection.
// TheBoolAttribut es.XmlDefaultVa lue = null; // Throws a
file not found exception
// TheBoolAttribut es.XmlDefaultVa lue = new object(); // Throws an
InvalidOperatio nException: The default value type, System.Object, is
unsupported.
// TheBoolAttribut es.XmlDefaultVa lue = ""; // Throws a
file not found exception
// TheBoolAttribut es.XmlDefaultVa lue = 6; // Throws a
file not found exception
ExplicitOverrid es.Add(typeof(S impleClass), "TheBool",
TheBoolAttribut es);

XmlSerializer SerializerOverr ides = new
XmlSerializer(I nstanceToSerial ize.GetType(), ExplicitOverrid es);
XMLStringWriter = new StringWriter();
SerializerOverr ides.Serialize( XMLStringWriter ,
InstanceToSeria lize);
Console.WriteLi ne("\nWITH Overrides: \n" +
XMLStringWriter .ToString());
}
}
}

// Sample Output:
//WITHOUT Overrides:
//<?xml version="1.0" encoding="utf-16"?>
//<ArrayOfSimpleC lass xmlns:xsd="http ://www.w3.org/2001/XMLSchema"
xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance">
//<SimpleClass>
//<TheString>I am true</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheBool>fals e</TheBool>
//<TheString>I am false</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheString>tr ue #2</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheBool>fals e</TheBool>
//<TheString>fals e #2</TheString>
//</SimpleClass>
//</ArrayOfSimpleCl ass>
//
//WITH Overrides:
//<?xml version="1.0" encoding="utf-16"?>
//<ArrayOfSimpleC lass xmlns:xsd="http ://www.w3.org/2001/XMLSchema"
xmlns:xsi="http ://www.w3.org/2001/XMLSchema-instance">
//<SimpleClass>
//<TheBool>true </TheBool>
//<TheString>I am true</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheString>I am false</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheBool>true </TheBool>
//<TheString>tr ue #2</TheString>
//</SimpleClass>
//<SimpleClass>
//<TheString>fals e #2</TheString>
//</SimpleClass>
//</ArrayOfSimpleCl ass>