[Mono-devel-list] XML (de)serialization

[Lluis Sanchez]

XmlSerializer wasn't working well on 0.24. Get updated code from CVS or wait
for 0.25 (to be released soon), it is very stable and complete now.

- Lluis

----- Original Message ----- 
From: "Herscovici, Avi" <AHerscovici at Empirix.com>
To: <mono-devel-list at lists.ximian.com>
Sent: Tuesday, June 24, 2003 5:03 PM
Subject: [Mono-devel-list] XML (de)serialization


> First project with mono/mcs and I've run into a couple problems.  I'm
> getting incorrect output from (XML) deserializing when attributes are
used.
> Serializing with attributes gives the same xml file as .net produces, but
> when deserializing, I get values from the default constructor and not the
> ones I assigned to the members of the object before I serialized it.  This
> works fine if I don't have any attributes (such as [XMLAttribute]).  Also,
> trying to serialize an inherited class causes an unhandled
> NullReferenceException to be thrown.  Can someone fill me in as to the
> status of xml serializing and deserializing?  I am willing to contribute
as
> this is critical to my project (more critical is deserializing XML in mono
> that is already serialized in .Net (windows)).  Below are code examples
for
> which I obtain errors and the errors:  (All of this is compiled with MCS
> 0.24 and run with mono 0.24)
>
> -Avi
>
> //------------------- serial-test.cs
> ----------------------------------------
>
> // Test what objects mono can serialize and De-serialize.
> using System;
> using System.Xml.Serialization;
> using System.IO;
> using System.Xml;
> using Test;
>
>
> namespace Serial.test {
>
> public class sertest {
>
> public static void Save(System.IO.Stream stream, object x)
> {
> XmlSerializer ser = new
> XmlSerializer(typeof(Script));
> ser.Serialize(stream, x);
> }
>
> public static void Save(string filename, object x)
> {
> FileStream str = new FileStream(filename,
> FileMode.Create, FileAccess.Write);
> Save(str, x);
> str.Close();
> }
>
> public static object Load(System.IO.Stream stream)
> {
> object s;
> Console.WriteLine("Debug line 1a");
> XmlSerializer ser = new
> XmlSerializer(typeof(Script));
> Console.WriteLine("Debug line 2a");
> // try {
> s = (object)ser.Deserialize(stream);
> // }
> // catch (Exception e) {Console.WriteLine("Exception: "
> + e);}
> // s = null;
> return s;
> }
>
>
> public static object Load(string filename)
> {
> object s;
> Console.WriteLine("Debug line 2");
> FileStream str = new FileStream(filename,
> FileMode.Open, FileAccess.Read);
> Console.WriteLine("Debug line 3");
> s = Load(str);
> Console.WriteLine("Debug line 4");
> str.Close();
> return s;
> }
>
> static void Main() {
>
> string filename = "test.ser";
>
> Script x =  new Script();
>
> x.X=0;
> x.Y=1;
> x.Z=2;
> x.String="TEST";
> x.Foo= new Bar();
> x.Foo.I=10;
>
> Save(filename, x);
>
> Script temp = (Script)Load(filename);
>
> Console.WriteLine("The values are: ");
> Console.WriteLine(temp.X);
> Console.WriteLine(temp.Y);
> Console.WriteLine(temp.Z);
> Console.WriteLine(temp.String);
> Console.WriteLine(temp.Foo.I);
>
>
>
> }
>
> }
>
> }
>
> // ------------------------ test.cs -----------------------------
>
> namespace Test
> {
> [XmlRoot(ElementName="Script", Namespace="http://www.foo.com")]
> public class Script
> {
> // Vars
> private int m_x;
> private int m_y;
> private int m_z;
> private string m_str;
> private Foo m_foo;
>
> // Constructor
> public Script()
> {
> m_x = -3;
> m_y = -2;
> m_z = -1;
> m_str = null;
> m_foo = null;
> }
>
> // Properties
> [XmlIgnore()]
> public int X
> {
> get { return m_x; }
> set { m_x = value; }
> }
>
> [XmlAttribute("y")]
> public int Y
> {
> get { return m_y; }
> set { m_y = value; }
> }
>
> [XmlAttribute("z")]
> public int Z
> {
> get { return m_z; }
> set { m_z = value; }
> }
>
> [XmlAttribute("str")]
> public string String
> {
> get { return m_str; }
> set { m_str = value; }
> }
>
>
> public Foo Foo
> {
> get { return m_foo; }
> set { m_foo = value; }
> }
> }
>
>
> [XmlInclude(typeof(Bar))]
> public class Foo
> {
> private int m_i;
> public int I
> {
> get { return m_i; }
> set { m_i = value; }
> }
> }
>
> [XmlRoot("Bar", Namespace="http://www.foo.com")]
> public class Bar : Foo
> {
> private int m_j;
> public int J
> {
> get { return m_j; }
> set { m_j = value; }
> }
> }
>
> }
>
> //------------------------------------------------- OUTPUT
> ----------------------------------------
>
> output that I get when I run this in .Net:
> Debug line 2
> Debug line 3
> Debug line 1a
> Debug line 2a
> Debug line 4
> The values are:
> -3
> 1
> 2
> TEST
> 10
>
> (which is correct, x.X has an ignore attribute)
>
> under linux:
> Unhandled Exception: System.NullReferenceException: A null value was found
> where an object instance was required
> in <0x00236> 00 System.Xml.Serialization.XmlSerializer:SerializeMembers
> (System.Xml.XmlWriter,object,bool)
> in <0x00795> 00 System.Xml.Serialization.XmlSerializer:WriteElement
>
(System.Xml.XmlWriter,System.Xml.Serialization.XmlAttributes,string,string,S
> ystem.Type,object)
> in <0x00eb1> 00 System.Xml.Serialization.XmlSerializer:SerializeMembers
> (System.Xml.XmlWriter,object,bool)
> in <0x00a02> 00 System.Xml.Serialization.XmlSerializer:Serialize
>
(System.Xml.XmlWriter,object,System.Xml.Serialization.XmlSerializerNamespace
> s)
> in <0x00071> 00 System.Xml.Serialization.XmlSerializer:Serialize
> (System.IO.Stream,object)
> in <0x00049> 00 Serial.test.sertest:Save (System.IO.Stream,object)
> in <0x0004a> 00 Serial.test.sertest:Save (string,object)
> in <0x00101> 00 Serial.test.sertest:Main ()
>
>
> (concerning the incorrect output with attributes)
> Now, if i comment out everything that has to do w/ Foo and Bar here is
what
> I get:
> Debug line 2
> Debug line 3
> Debug line 1a
> Debug line 2a
> Debug line 4
> The values are:
> -3
> -2
> -1
>
> (incorrect)
>
> If I keep that commented out and also comment out all the attributes I
get:
> Debug line 2
> Debug line 3
> Debug line 1a
> Debug line 2a
> Debug line 4
> The values are:
> 0
> 1
> 2
> TEST
>
> (which is the correct result)...
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