Question

Just for some fun I was playing with the API of Last.fm. The XML file they return for top artists is structured like this:

<lfm status="ok">
 <topartists user="xbonez" type="overall">
  <artist rank="1">
  <name>Evanescence</name> 
  <playcount>4618</playcount> 
  <mbid>f4a31f0a-51dd-4fa7-986d-3095c40c5ed9</mbid> 
  <url>http://www.last.fm/music/Evanescence</url> 
  <streamable>1</streamable> 
  <image size="small">http://userserve-ak.last.fm/serve/34/48488613.png</image> 
  <image size="medium">http://userserve-ak.last.fm/serve/64/48488613.png</image> 
  <image size="large">http://userserve-ak.last.fm/serve/126/48488613.png</image> 
  <image size="extralarge">http://userserve-ak.last.fm/serve/252/48488613.png</image> 
  <image size="mega">http://userserve-ak.last.fm/serve/500/48488613/Evanescence++PNG.png</image> 
  </artist>
 </topartists>
</lfm>

This is how I’m deserealizing it.

I have a class called lfmStatus:

    [Serializable()]
        [XmlRootAttribute("lfm")]
        public class lfmStatus
        {
            [XmlElement("artist")]
            public List<Artists> TopArtists { get; set; }         
        }

And a Class Artists:

[Serializable()]
    public class Artists
    {
        [XmlElement("name")]
        public string Name { get; set; }

        [XmlElement("playcount")]
        public int playcount { get; set; }

        [XmlElement("url")]
        public string url { get; set; }

        [XmlElement("streamable")]
        public int streamable { get; set; }

        [XmlElement("image")]
        public string image { get; set; }

    }

And then I deserealize using this code:

string XmlFile = "artists.xml";
            XmlSerializer serializer = new XmlSerializer(typeof(lfmStatus));

            lfmStatus LoadFile;

            using (Stream reader = new FileStream(XmlFile, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
            {
                try
                {
                    Console.WriteLine("Beginning deserialization.");

                    // Call the Deserialize method to restore the object's state.
                    LoadFile = (lfmStatus)serializer.Deserialize(reader);

                    return LoadFile.TopArtists;
                }

Now, this code works great for the XML if it did not have the topartists tag enveloping all the artists. But since it does, how do I change my code to handle that? I’m assuming I need to add another class.

Answer 1

You are missing the attribute(s) on a few types.

See XmlAttributeAttribute for more detail.

You are also missing the topartists element’s type.

If I was you, I would get the XML schema and just use xsd.exe to generate the C# classes, and modify from there. It can also infer the schema based on XML if you really can’t find it, this will give you a parsable result based on the input XML.