Deserialization with XmlSerializer

Question

I'm writing a Windows Store App and I need to store some data in Roaming Storage; for that I needed to serialize/deserialize some data. My serializer/deserializer functions are as below:

public string Serialize()
    {
        try
        {
            StringWriter sw = new StringWriter();

            XmlSerializer xs = new XmlSerializer(typeof(RssData));
            xs.Serialize(sw, this);


            return sw.ToString();
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine(ex);
            return String.Empty;
        }
    }

    public void Deserialize(string serialized)
    {
        try
        {
            XmlSerializer xs = new XmlSerializer(typeof(RssData));
            XmlReader xr = XmlReader.Create(new StringReader(serialized));
            RssData rd = xs.Deserialize(xr) as RssData;
            this.categoryList = rd.categoryList;
            this.defaultCategory = rd.defaultCategory;
        }
        catch(Exception ex)
        {
            System.Diagnostics.Debug.WriteLine(ex);
        }
    }

In summary, RssData has a list of RssCategory, and each RssCategory has a RssFeed. There is no problem with serialization and the following string is an example that I've produced using the Serialize function above:

<?xml version="1.0" encoding="utf-16"?>
<RssData xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <CategoryList>
    <RssCategory>
      <Name>No Category</Name>
      <RssList>
        <RssFeed>
          <Title>HABERTURK.COM</Title>
          <Url>http://www.haberturk.com/rss</Url>
          <Image>http://www.haberturk.com/images/htklogo2.jpg</Image>
          <Subtitle>HABERTÜRK - Türkiye'nin En Büyük İnternet Gazetesi</Subtitle>
        </RssFeed>
      </RssList>
    </RssCategory>
  </CategoryList>
</RssData>

However, when I Deserialize this XML, the resulting RssData has a CategoryList with 2 RssCategories, one is a RssCategory named "No Category" with an empty RssList, the other one is the correct one as defined in the XML; i.e. "No Category" with one RssFeed.

Is it a problem with my code or is XmlSerializer bugged?

Sorry for the duplicate: http://stackoverflow.com/questions/9589589/deserializing-listint-with-xmlserializer-causing-extra-items?rq=1 — mostruash, Jan 21 '13 at 11:31

mostruash · Accepted Answer · 2013-01-21T11:26:23.370

Ok it seems that XmlSerializer first constructs the object using its no-parameter constructor then adds each item in the XML to the appropriate list. Thus if the constructor adds some items to that list, deserializing will result in a list that includes any item added in the constructor.

Edit: So if you serialize/deserialize a class that has a property of type Array/List/Container etc, in the no-parameter constructor you have to initialize it, but do not add anything to it.

score 0 · Answer 2 · answered Jan 21 '13 at 11:18

0

Try this out and tell me:

Class c = new Class(); //class name of data which was serialized using (var sr = new StringReader(Serialized data, wherever you are fetching it from) { var xs = new XmlSerializer(typeof(Class)); c= (Class)xs.Deserialize(sr); }

answered Jan 21 '13 at 11:18

SutharMonil

78
3
19

There is no difference between this code and my code that I've put in my question. The problem was with the constructor of the class that is being serialized. Check my answer. – mostruash Jan 21 '13 at 11:23

Deserialization with XmlSerializer

2 Answers2