DataContract XML serialization and XML attributes

Question

Is it possible to deserialize this XML into an object marked with the DataContract attribute?

<root>
<distance units="m">1000</distance>
</root>

As you may see there is "units" attribute. I don't believe that's supported. Or am I wrong?

Greg Sansom · Accepted Answer · 2013-11-11T03:06:21.877

59

This can be achieved, but you will have to override the default serializer by applying the [XmlSerializerFormat] attribute to the DataContract. Although it can be done, this does not perform as well as the default serializer, so use it with caution.

The following class structure will give you the result you are after:

using ...
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Xml.Serialization;

[DataContract]
[XmlSerializerFormat]
public class root
{
   public distance distance=new distance();
}

[DataContract]
public class distance
{
  [DataMember, XmlAttribute]
  public string units="m";

  [DataMember, XmlText]
  public int value=1000;
}

You can test this with the following code:

root mc = new root();
XmlSerializer ser = new XmlSerializer(typeof(root));
StringWriter sw = new StringWriter();
ser.Serialize(sw, mc);
Console.WriteLine(sw.ToString());
Console.ReadKey();

The output will be:

<?xml version="1.0" encoding="utf-16"?>
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                                   xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <distance units="m">1000</distance>
</root>

edited Nov 11 '13 at 03:06

answered Feb 01 '11 at 05:02

Greg Sansom

20,442
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9

If you are looking for the XmlSerializerFormat attribute, you can find it in the System.ServiceModel namespace : http://msdn.microsoft.com/en-us/library/system.servicemodel.xmlserializerformatattribute%28v=VS.90%29.aspx – jeffreypriebe Oct 23 '11 at 01:16
1

Sure, that works for coding, I like to read the reading the docs as well :) – jeffreypriebe Oct 24 '11 at 18:44
@GregSansom, that assumes that you've already added the reference. Resolve doesn't appear as an option if you haven't. – Dan Esparza Oct 08 '13 at 19:49
So this seems to work by using a mix of DataContract attributes and then XmlSerialization attribute XmlAttribute, which I didn't reallize you could do, I thought it was one or the other. Does the XmlSerializer ignore the DataContract attributes? – AaronLS Apr 01 '14 at 22:05
2

@AaronLS i just tried this and it appears to ignore the DataContact attributes. I tried to set the name `[DataMember(Name = "foo")]` but it was not serialized using that name, but rather the declared property name instead. – Sinaesthetic Jul 25 '16 at 21:52
1

@Sinaesthetic Yes, so it seems if you use Data Contract Serializer, you use DataContract/Member attributes to define structure. If you use XmlSerializer, then you need to use Xml* attributes to define structure. – AaronLS Jul 26 '16 at 14:56

score 33 · Answer 2 · edited Feb 23 '17 at 22:50

The Data Contract Serializer used by default in WCF does not support XML attributes for performance reasons (the DCS is about 10% faster on average than the XML serializer).

So if you really want to use the DCS, you cannot use this structure you have - it would have to be changed.

Or you need to use the XmlSerializer with WCF, as Greg showed in his answer - that works, too, but you lose the performance benefit (plus all other benefits) of the DCS.

DataContract XML serialization and XML attributes

2 Answers2

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