private object GetElementDefaultValue (XmlSchemaElement elem)
{
// Unlike attribute, element cannot have a default value.
if (elem.RefName == XmlQualifiedName.Empty)
return elem.DefaultValue;
XmlSchemaElement referenced = schema.Elements [elem.RefName] as XmlSchemaElement;
if (referenced == null) // considering missing sub components
return null;
return referenced.DefaultValue;
}