How can I force the use of an xsi:type attribute?

Question

How can I force .NET\'s XmlSerializer to add an xsi:type=\"FooClass\" to a member/node of type FooClass?

The scenario

Answer 1

XmlSerializer can be pretty dumb and straightforward at times, which works to your advantage in this case. Just put it there manually:

public class FooClass
{
    public int FooPropertyA { get; set; }
    public string FooPropertyB { get; set; }

    [XmlAttribute("type", Namespace="http://www.w3.org/2001/XMLSchema-instance")]
    public string XsiType
    {
        get { return "Foo"; }
        set { }
    }
}