Serialization from Xml into Object

First, I should state that this post refers to a Silverlight 4 application. Silverlight 4 seems to have a cut-down version of the Serialization model.

I have an XML file in the following format:

Code:

---

<?xml version="1.0" standalone="yes"?>
<TeamTable>
  <TeamRow Id="1" Name="Arsenal" />
  <TeamRow Id="2" Name="Aston Villa" />
  <TeamRow Id="3" Name="Blackburn Rovers" />
  <TeamRow Id="4" Name="Bolton Wanderers" />
  <TeamRow Id="5" Name="Chelsea" />
  ...
</TeamTable>

---

I read the XML into an XDocument and then call the Load(...) member on my TeamTable Class:

Code:

---

    public class TeamTable : List<TeamRow>
    {
        public void Load(XDocument document)
        {
            foreach (XElement element in document.Descendants("TeamRow"))
                this.Add(TeamRow.Load(element));
        }
    }

---

For each of the TeamRow elements in the document, this function calls the Load(...) member of my TeamRow class:

Code:

---

    [DataContract]
    public class TeamRow
    {
        [DataMember]
        public Int32 Id { get; set; }

        [DataMember]
        public String Name { get; set; }

        public TeamRow() { }

        public static TeamRow Load(XElement element)
        {
            DataContractSerializer serializer = new DataContractSerializer(typeof(TeamRow));

            using (XmlReader reader = element.CreateReader())
            {
                return serializer.ReadObject(reader) as TeamRow;
            }
        }
    }

---

All appears to be well, the first element passed to this function contains

<TeamRow Id="1" Name="Arsenal" />

as I would expect.

However the ReadObject(...) function is throwing the following exception.

Code:

---

Expecting element 'TeamRow' from namespace 'http://schemas.datacontract.org/2004/07/...'..
 Encountered 'Element'  with name 'TeamRow', namespace".

---

This is my first attempt at this type of serialization. Can anyone help me fix the exception?

try changing your DataContractSerializer to this:

Code:

---

DataContractSerializer serializer = new DataContractSerializer(typeof(TeamRow), "TeamRow", "");

---

Thanks Joe.

That has cleared the exception and now I have a list of 20 (the number of teams) TeamRow's. However, each entry in the list has:

Id = 0
Name = null

I'll continue on with my trial and error to see if I can work out why, but any further help is appreciated.

Debugging confirms that the 'set' accessor on the TeamRow.Id property NEVER gets called.

I was assuming that the DataContractSerializer would call those to set their values during the ReadObject() call.

Still stuck.

Does Silverlight support the XmlSerializer class?

If so, create a couple of classes with Xml attributes:

Code:

---

namespace CG
{
  #region Using Directives
  using System;
  using System.Collections.Generic;
  using System.Xml;
  using System.Xml.Serialization;
  #endregion Using Directives

  ///<summary>
  /// Serialization class used to read the teamtable
  ///</summary>
  [Serializable]
  [XmlType( AnonymousType = true )]
  [XmlRoot( ElementName = "TeamTable", Namespace = "", IsNullable = false )]
  publicclassTeams
  {
    ///<summary/>
    publicstaticTeams Open( string configFile )
    {
      var serializer = newXmlSerializer( typeof( Teams ) );

      using ( var reader = XmlReader.Create( configFile ) )
      {
        return ( Teams ) serializer.Deserialize( reader );
      }
    }

    ///<remarks/>
    [XmlElement( "TeamRow", IsNullable = false )]
    publicTeam [ ] Rows
    {
      get
      {
        return _rows.ToArray( );
      }
      set
      {
        if ( null == _rows )
        {
          _rows = newList<Team>( );
        }
        _rows.AddRange( value );
      }
    }
   
    privateList<Team> _rows = newList<Team>( );
  }

  ///<remarks/>
  [Serializable]
  [XmlType( AnonymousType = true )]
  publicclassTeam
  {
    ///<remarks/>
    [XmlAttribute( AttributeName = "Id" )]
    publicint Id { get { return _id; } set { _id = value; } }

    ///<remarks/>
    [XmlAttribute( AttributeName = "Name" )]
    publicstring Name { get { return _name; } set { _name = value; } }


    privateint _id;
    privatestring _name;
  }
}

---

Then loading up the xml is:

Code:

---

var teamList = newList<Team>( );

// Loads the xml into a Teams instance
var teams = Teams.Open("teams.xml"); 
 
// Retrieve the TeamRows
teamList.AddRange( teams.Rows );

---

Arjay... the reason I looked in to serialization as an option for solving my problem was due to a similar post you posted the other day on another thread ;)

No, I don't believe XmlSerializers are supported fully in Silverlight, however DataContract's are. After much messing about (especially with namespaces in the XML) I solved my problem and then refactored again and again to arrive at this fairly neat and generic solution.

Example XML:

Code:

---

<?xml version="1.0" encoding="utf-8"?>
<Table xmlns:S8="http://schemas.datacontract.org/2004/07/MyAppName" xmlns="S8">
        <Row>
                <S8:Id>1</S8:Id>
                <S8:SectionId>4</S8:SectionId>
                <S8:Name>Arsenal</S8:Name>
        </Row>
        <Row>
                <S8:Id>2</S8:Id>
                <S8:SectionId>2</S8:SectionId>
                <S8:Name>Aston Villa</S8:Name>
        </Row>
</Table>

---

My Team class:

Code:

---

    [DataContract(Name="Row")]
    public class Team
    {
        [DataMember(Order = 0)]
        public Int32 Id { get; set; }

        [DataMember(Order = 1)]
        public Int32 SectionId { get; set; }

        [DataMember(Order = 2)]
        public String Name { get; set; }
    }

---

And my new generic Table class replacing TeamTable (as I will have many more tables).

Code:

---

    [CollectionDataContract(Namespace = "S8")]
    public class Table<T> : List<T>
    {
        public static Table<T> Load(String tableXml)
        {
            using (StringReader stringReader = new StringReader(tableXml))
            {
                DataContractSerializer serializer = new DataContractSerializer(typeof(Table<T>), "Table", "S8");

                using (XmlReader xmlReader = XmlReader.Create(stringReader))
                {
                    return (serializer.ReadObject(xmlReader) as Table<T>);
                }
            }
        }
    }

---

Now all I have to do is create XML files in similar format to the above Table/Row tags and namespaces and create a supporting class similar to Team and from my main code I can do the following:

Code:

---


        private Table<Team> _teams;
        private Table<Section> _sections;
        private Table<Entry> _entries;

        _teams = Table<Team>.Load(teamTableXml);
        _sections = Table<Section>.Load(sectionTableXml);
        _entries = Table<Entry>.Load(entryXml);

---

Quote:

---

Originally Posted by rliq

Arjay... the reason I looked in to serialization as an option for solving my problem was due to a similar post you posted the other day on another thread ;)

---

Cool. I consider a day that I can avoid any xml document work a good day. :D


-------------------------------------------
Arjay

See my latest series on using WCF to communicate between a Windows Service and WPF task bar application.
Tray Notify - Part I Tray Notify - Part II

Need a little help with Win32 thread synchronization? Check out the following CG articles and posts:
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Simple Thread: Part I [Simple Thread: Part II
Win32 Thread Synchronization, Part I: Overview Win32 Thread Synchronization, Part 2: Helper Classes

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