How to include null properties during xml serialization

Question

Currently, the code below omits null properties during serialization. I want null valued properties in the output xml as empty elements. I searched the web but didn't find anything useful. Any help would be appreciated.

        var serializer = new XmlSerializer(application.GetType());
        var ms = new MemoryStream();
        var writer = new StreamWriter(ms);
        serializer.Serialize(writer, application);
        return ms;

Sorry, I forgot to mention that I want to avoid attribute decoration.

A couple of dupes: [XML Serialization and null value - C#](http://stackoverflow.com/questions/711723/xml-serialization-and-null-value-c-sharp) and [XmlSerializer. Keep null string properties?](http://stackoverflow.com/questions/10733731/xmlserializer-keep-null-string-properties) — Darin Dimitrov, Aug 29 '13 at 15:34
Careful, empty elements are _not equatable_ to non-existing/null elements. For example, XML serializing a `string` property, an empty element will produce an empty string `""` (`String.Empty`) for that property, where as a non-existing (or an element with `xsi:nil="true"` attribute) element will produce a `null` reference value for that same property. — Chris Sinclair, Aug 29 '13 at 16:08

score 27 · Accepted Answer · answered Aug 29 '13 at 15:34

27

Can you control the items that have to be serialized?
Using

[XmlElement(IsNullable = true)]
public string Prop { get; set; }

you can represent it as <Prop xsi:nil="true" />

answered Aug 29 '13 at 15:34

Emanuele Greco

12,551
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score 1 · Answer 2 · answered Aug 29 '13 at 15:39

You can use also use the following code. The pattern is ShouldSerialize{PropertyName}

public class PersonWithNullProperties
{
    public string Name { get; set; }
    public int? Age { get; set; }
    public bool ShouldSerializeAge()
    {
        return true;
    }
}

  PersonWithNullProperties nullPerson = new PersonWithNullProperties() { Name = "ABCD" };
  XmlSerializer xs = new XmlSerializer(typeof(nullPerson));
  StringWriter sw = new StringWriter();
  xs.Serialize(sw, nullPerson);

XML

<?xml version="1.0" encoding="utf-16"?>
<Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://
www.w3.org/2001/XMLSchema">
  <Name>ABCD</Name>
  <Age xsi:nil="true" />
</Person>

score 0 · Answer 3 · edited Oct 14 '16 at 13:13

0

Set the XmlElementAttribute.IsNullable property:

https://msdn.microsoft.com/en-us/library/system.xml.serialization.xmlelementattribute.isnullable(v=vs.110).aspx

edited Oct 14 '16 at 13:13

Tim Abell

11,186
8
79
110

answered Aug 29 '13 at 15:35

user2722002

65
1
6

How to include null properties during xml serialization

3 Answers3

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