How do I stop an empty tag from being emitted by XmlSerializer?

Question

I have an object like this,

public class UserObj
{
    public string First {get; set;}
    public string Last  {get; set;}
    public addr Address {get; set;}

}

public class addr
{
    public street {get; set;}
    public town   {get; set;}
}

Now when I use XmlSerializer on it and street and town are empty I get this in the XML output,

 <Address />

Is there a way not to output this empty tag?

Thanks

Answer 1

You may implement IXmlSerializable and implement the serialization routine on your own. This way, you can avoid the element.

An example here: http://paltman.com/2006/jul/03/ixmlserializable-a-persistable-example/

Answer 2

You can implement a ShouldSerializeAddress method to decide whether or not the Address property should be serialized :

public bool ShouldSerializeAddress()
{
    return Address != null
        && !String.IsNullOrEmpty(Address.street)
        && !String.IsNullOrEmpty(Address.town);
}

If the method exists with this signature, the serializer will call it before serializing the property.

Alternatively, you can implement an AddressSpecified property which has the same role :

public bool AddressSpecified
{
    get
    {
        return Address != null
            && !String.IsNullOrEmpty(Address.street)
            && !String.IsNullOrEmpty(Address.town);
    }
}

Answer 3

You can eliminate the empty value by adding a DefaultValue attribute to the property. When the value of the property matches the default value, it isn't serialized. You set the default value to null, to eliminate the serialization. Here's an example:

using System.ComponentModel;
public class UserObj
{
    public string First {get; set;}
    public string Last  {get; set;}

    [DefaultValue(null)]
    public addr Address {get; set;}

}

Answer 4

I think assigning null value to address field should work.