public class XmlSerializerNamespaces {
// Public Constructors
   public XmlSerializerNamespaces( );  
   public XmlSerializerNamespaces( System.Xml.XmlQualifiedName[ ] namespaces);  
   public XmlSerializerNamespaces( XmlSerializerNamespaces namespaces);  
// Public Instance Properties
   public int Count{get; } 
// Public Instance Methods
   public void Add( string prefix, string ns);  
   public XmlQualifiedName[ ] ToArray( );  
}

This type provides a collection of XML namespaces and namespace prefixes that the XmlSerializer uses to determine the qualified names of nodes when serializing an object to an XML document. To assign a namespace to a node, set the XmlElementAttribute.Namespace or XmlAttributeAttribute.Namespace property. This can be done either by attaching the attribute to a member in the code, or by assigning the attribute in the XmlAttributeOverrides class.