//識別需要序列化的型別
        private static readonly Type[] WriteTypes = new[] {
            typeof(string), typeof(DateTime), typeof(Enum),
            typeof(decimal?), typeof(Guid),typeof(int?)
        };
        public static bool IsSimpleType(this Type type)
        {
            return type.IsPrimitive || WriteTypes.Contains(type);
        }
        public static object ToXml(this object input)
        {
            return input.ToXml(null);
        }

        public static object ToXml(this object input, string element = "ROOT")
        {
            if (input == null)
                return null;

            if (string.IsNullOrEmpty(element))
                element = "ROOT";
            element = XmlConvert.EncodeName(element);
            var ret = new XElement(element);

            if (input != null)
            {
                var type = input.GetType();

                if (input is IEnumerable && !type.IsSimpleType())
                {
                    var elements = (input as IEnumerable<object>)
                        .Select(m => m.ToXml(element))
                        .ToArray();

                    return elements;
                }
                else
                {
                    var props = type.GetProperties();
                    var elements = from prop in props
                                   let name = XmlConvert.EncodeName(prop.Name)
                                   let val = prop.GetValue(input, null)
                                   let value = prop.PropertyType.IsSimpleType()
                                        ? new XElement(name, val)
                                        : val.ToXml(name)
                                   where value != null
                                   select value;
                    ret.Add(elements);
                }
            }
            return ret;
        }
 

            var xx = new
            {
                HEADER = new { TRADEMSG = "", MACHINEID = "" },
                BODY = new
                {
                    ITEM = ITEM.Select(p => new
                    {
                        p.BRID,
                        p.BRXM
                    }).ToList(),
                }
            };

            var aa = xx.ToXml();