Controlling order of serialization in asp net c#

use Order with XmlElement

public class ItemGroup
{
    [XmlElement(Order = 0)]
    public Reference Reference { get; set; }
    [XmlElement(Order = 1)]
    public Reference None { get; set; }
    [XmlElement(Order = 2)]
    public Reference Content { get; set; }
    [XmlElement(Order = 3)]
    public Reference Compile { get; set; }
}