How to include properties with default values while serializing with XMLSerializer in c#

Question

By default, the XMLSerializer will ignore the properties with default values while performing the serialization. But I do have a special case where every property has to be serialized irrespective of the default values.

At the same time, default value attributes are serving other purposes for which I cannot remove the DefaultValueAttribute.

To be precise, I cannot remove the DefaultValueAttribute and at the same time, I want all the properties to be serialized using XML serializer.

Thanks in advance

Answer 1

First way.

Create a data transfer object. With the same set of properties as the original class, but without the DefaultValue attributes.

For example you have

public class Person
{
    [DefaultValue(30)]
    public int Age { get; set; }
    public string Name { get; set; }
}

Create

public class PersonDto
{
    public int Age { get; set; }
    public string Name { get; set; }
}

Serialize like this:

var person = new Person { Age = 30, Name = "John" }; // original object

var personDto = new PersonDto { Age = person.Age, Name = person.Name }; // DTO

var xs = new XmlSerializer(typeof(PersonDto));
xs.Serialize(someStream, personDto);

Of course, you can use automatic mapping from one object type to another. Like AutoMapper.

---

Second way.

Use XmlAttributeOverrides.

var person = new Person { Age = 30, Name = "John" };

var overrides = new XmlAttributeOverrides();
var attrs = new XmlAttributes();
attrs.XmlElements.Add(new XmlElementAttribute("Age"));
overrides.Add(typeof(Person), nameof(Person.Age), attrs);

var xs = new XmlSerializer(typeof(Person), overrides);
xs.Serialize(someStream, person);

Now it will serialize default value.