Only serialize List property when not empty

Question

In web api, I'm serializing a class that contains properties that are IEnumerable and I only want the properties to be serialized if they are not empty collections.

[DataMember(EmitDefaultValue = false)] does not work because the properties are not null since they are initialized in the constructor.

[DataContract]
public class Linkable : ILinkable {

    [DataMember(EmitDefaultValue = false)]
    public IList<ILink> links { get; set; }

    [DataMember(EmitDefaultValue = false)]
    public IList<ILink> linkTemplates { get; set; }

    public Linkable() {
        links = new List<ILink>();
        linkTemplates = new List<ILink>();
    }
}

Is there a way to do this with an Attribute ? If not, how can I accomplish this?

Answer 1

Can you just leave the collections null until you need to add something to them? For example:

public class Linkable {
    public IList<ILink> links { get; set; }

    public void AddLink(ILink link) {
        if (links == null) {
            links = new List<ILink>();
        }
        links.Add(link);
    }
}