How to exclude null properties when using XmlSerializer

Question

I'm serializing a class like this

public MyClass
{
    public int? a { get; set; }
    public int? b { get; set; }
    public int? c { get; set; }
}

All of the types are nullable because I want minimal data stored when serializing an object of this type. However, when it is serialized with only "a" populated, I get the following xml

<MyClass ...>
    <a>3</a>
    <b xsi:nil="true" />
    <c xsi:nil="true" />
</MyClass>

How do I set this up to only get xml for the non null properties? The desired output would be

<MyClass ...>
    <a>3</a>
</MyClass>

I want to exclude these null values because there will be several properties and this is getting stored in a database (yeah, thats not my call) so I want to keep the unused data minimal.

Answer 1

You ignore specific elements with specification

public MyClass
{
    public int? a { get; set; }

    [System.Xml.Serialization.XmlIgnore]
    public bool aSpecified { get { return this.a != null; } }

    public int? b { get; set; }
    [System.Xml.Serialization.XmlIgnore]
    public bool bSpecified { get { return this.b != null; } }

    public int? c { get; set; }
    [System.Xml.Serialization.XmlIgnore]
    public bool cSpecified { get { return this.c != null; } }
}

The {field}Specified properties will tell the serializer if it should serialize the corresponding fields or not by returning true/false.