Deserialize XML values to objects

Question

I'm trying to use XDocument to read in XML and deserialize it to objects.

I want to take the following XML:

<r25:spaces xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xl="http://www.w3.org/1999/xlink" xmlns:r25="http://www.collegenet.com/r25" pubdate="2019-07-15T14:51:16-07:00" engine="accl">
  <r25:space crc="00000022" status="est" xl:href="space.xml?space_id=200">
    <r25:space_id>200</r25:space_id>
    <r25:space_name>LRN 0001</r25:space_name>
    <r25:formal_name>Learning Commons -Test Scheduling Room</r25:formal_name>
    <r25:partition_id xl:href="rmpart.xml?partition_id=2">2</r25:partition_id>
    <r25:last_mod_dt>2019-07-11T08:01:00-07:00</r25:last_mod_dt>
  </r25:space>
</r25:spaces>

and deserialize it to a List of spaces (where Space has the following definition):

public class Space
{
    public long space_id { get; set; }
    public string space_name { get; set; }
    public string formal_name { get; set; }
    public long partition_id { get ; set; }
    public DateTime last_mod_dt { get; set; }
}

I've only gotten so far as to get the XElement. It dies on the serializer

var doc = XDocument.Parse(result.Content);
XNamespace ns = "http://www.collegenet.com/r25";
XElement el = doc.Element(ns + "spaces");

foreach (var space in el.Elements())
{
    var serializer = new XmlSerializer(typeof(Space));
    var s = (Space)serializer.Deserialize(space.CreateReader());
}

All I'm getting when I try to use XmlSerializer is "There is an error in XML document (0,0)", which isn't very helpful. I've updated my post with what I've tried. — Emily Johnson
– Emily Johnson, Commented Jul 15, 2019 at 22:12
If you are using XDocument, you aren't really deserializing-- you are parsing. You can either parse or deserialize-- there is no need to do both. If you're OK with a parsing approach, see David Browne's answer, which I am upvoting. — John Wu
– John Wu, Commented Jul 15, 2019 at 23:14
You're on the right lines here in that you were using the namespace for the XElement bit but when you retrieve that element and do the CreateReader() the namespaces are all still a factor and you have to let the XmlSerializer know about them using the serialization attribute XmlRootAttribute as shown in @SimplyGed's answer. You could also remove the XDocument stuff and read the XML straight from the string using an XmlTextReader. — dezfowler
– dezfowler, Commented Jul 15, 2019 at 23:32

Dale K · Accepted Answer · 2019-07-16 02:42:12Z

3

You can simply use LINQ to XML here. e.g.

using System;
using System.Linq;
using System.Xml.Linq;

namespace ConsoleApp22
{

    public class Space
    {
        public long space_id { get; set; }
        public string space_name { get; set; }
        public string formal_name { get; set; }
        public long partition_id { get; set; }
        public DateTime last_mod { get; set; }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var xml = @"
<r25:spaces xmlns:xsi=""http://www.w3.org/2001/XMLSchema-instance"" xmlns:xl=""http://www.w3.org/1999/xlink"" xmlns:r25=""http://www.collegenet.com/r25"" pubdate=""2019-07-15T14:51:16-07:00"" engine=""accl"">
  <r25:space crc=""00000022"" status=""est"" xl:href=""space.xml?space_id=200"">
    <r25:space_id>200</r25:space_id>
    <r25:space_name>LRN 0001</r25:space_name>
    <r25:formal_name>Learning Commons -Test Scheduling Room</r25:formal_name>
    <r25:partition_id xl:href=""rmpart.xml?partition_id=2"">2</r25:partition_id>
    <r25:last_mod_dt>2019-07-11T08:01:00-07:00</r25:last_mod_dt>
  </r25:space>
</r25:spaces>
";
            var doc = XDocument.Parse(xml);
            XNamespace ns = "http://www.collegenet.com/r25";

            var q = from e in doc.Element(ns + "spaces").Elements()
                    select new Space
                    {
                        space_id = (int)e.Element(ns + "space_id"),
                        space_name = (string)e.Element(ns + "space_name"),
                        formal_name = (string)e.Element(ns + "formal_name"),
                        partition_id = (long)e.Element(ns + "partition_id"),
                        last_mod = (DateTime)e.Element(ns + "last_mod_dt")
                    };

            var space = q.First();
        }
    }
}

edited Jul 16, 2019 at 2:42

Dale K

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answered Jul 15, 2019 at 22:44

David Browne - Microsoft

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3 Comments

Simply Ged Over a year ago

Nice answer, but aren't you just duplicating what the deserializer does?

David Browne - Microsoft Over a year ago

Avoiding the XmlSerializer, actually. Querying over the XML to create a custom projection is simple, useful, and not really something the XmlSerializer can do. So just an alternative approach.

Emily Johnson Over a year ago

Very nice solution. I'm still wanting to have automatic mapping, but if I need to, this works beautifully.

Simply Ged · Accepted Answer · 2019-07-15 23:00:11Z

1

You can add the XmlRoot to your class to declare the namespace for that element:

[XmlRoot("space", Namespace = "http://www.collegenet.com/r25")]
public class Space
{
    public long space_id { get; set; }
    public string space_name { get; set; }
    public string formal_name { get; set; }
    public long partition_id { get; set; }
    public DateTime last_mod { get; set; }
}

The deserializer will now correctly read the XML as an object.

answered Jul 15, 2019 at 23:00

Simply Ged

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Comments

Tony Stark · Accepted Answer · 2019-07-15 23:11:55Z

0

Use the the XSD tool to generate the class and then use XmlSerializer to populate the class. Like this.

MyClass myClass;
using (var stream = new FileStream("myClass.xml", FileMode.Open))
{
    var serializer = new XmlSerializer(typeof(MyClass));
    myClass = serializer.Deserialize(stream);
}

edited Jul 15, 2019 at 23:11

answered Jul 15, 2019 at 23:01

Tony Stark

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Comments

Emily Johnson · Accepted Answer · 2019-07-16 16:52:18Z

I found a website that will take XML and create the proper deserialization classes. Xml2CSharp, which created the following classes that allowed the deserialization to work:

[XmlRoot(ElementName="partition_id", Namespace="http://www.collegenet.com/r25")]
public class Partition_id {
    [XmlAttribute(AttributeName="href", Namespace="http://www.w3.org/1999/xlink")]
    public string Href { get; set; }
    [XmlText]
    public string Text { get; set; }
}

[XmlRoot(ElementName="space", Namespace="http://www.collegenet.com/r25")]
public class Space {
    [XmlElement(ElementName="space_id", Namespace="http://www.collegenet.com/r25")]
    public string Space_id { get; set; }
    [XmlElement(ElementName="space_name", Namespace="http://www.collegenet.com/r25")]
    public string Space_name { get; set; }
    [XmlElement(ElementName="formal_name", Namespace="http://www.collegenet.com/r25")]
    public string Formal_name { get; set; }
    [XmlElement(ElementName="partition_id", Namespace="http://www.collegenet.com/r25")]
    public Partition_id Partition_id { get; set; }
    [XmlElement(ElementName="last_mod_dt", Namespace="http://www.collegenet.com/r25")]
    public string Last_mod_dt { get; set; }
    [XmlAttribute(AttributeName="crc")]
    public string Crc { get; set; }
    [XmlAttribute(AttributeName="status")]
    public string Status { get; set; }
    [XmlAttribute(AttributeName="href", Namespace="http://www.w3.org/1999/xlink")]
    public string Href { get; set; }
}

[XmlRoot(ElementName="spaces", Namespace="http://www.collegenet.com/r25")]
public class Spaces {
    [XmlElement(ElementName="space", Namespace="http://www.collegenet.com/r25")]
    public Space Space { get; set; }
    [XmlAttribute(AttributeName="xsi", Namespace="http://www.w3.org/2000/xmlns/")]
    public string Xsi { get; set; }
    [XmlAttribute(AttributeName="xl", Namespace="http://www.w3.org/2000/xmlns/")]
    public string Xl { get; set; }
    [XmlAttribute(AttributeName="r25", Namespace="http://www.w3.org/2000/xmlns/")]
    public string R25 { get; set; }
    [XmlAttribute(AttributeName="pubdate")]
    public string Pubdate { get; set; }
    [XmlAttribute(AttributeName="engine")]
    public string Engine { get; set; }
}

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