更新后的xmlserializer值在反序列化

Question

在函数ChangeNodeValues中对子XmlNode进行更改后，一切正常，我可以看到调试时所做的更改。但是，在deserializeUnits数组中稍后检入后，将Price属性设置为零。我做错了什么？

var deserializedUnits = new List<XMLImportClasses.Object>();    
foreach (XmlNode node in doc.ChildNodes[0].ChildNodes)
{    
    ChangeNodeValues(node);
    using ( MemoryStream stm = new MemoryStream())
    {
        using (StreamWriter stw = new StreamWriter(stm))
        {
            stw.Write(node.OuterXml);
            stw.Flush();
            stm.Position = 0;
            XmlSerializer ser = new XmlSerializer(typeof( XMLImportClasses.Object));
            XMLImportClasses.Object result = (ser.Deserialize(stm) as XMLImportClasses.Object);
            deserializedUnits.Add(result);
        }
    }
}

private void ChangeNodeValues(XmlNode _node)
{
    foreach (XmlNode groupNode in _node.ChildNodes)
    {
        if(groupNode.Name == "Prices")
            foreach (XmlNode priceNode in groupNode.ChildNodes)
            {
                var strPrice = priceNode.InnerText;
                if (strPrice.Count() > 1)
                {
                    strPrice = (Convert.ToInt32(strPrice) + 5).ToString();
                    priceNode.InnerText = strPrice;
                }
            }
    }
}

编辑：对象，价格和价格等级：

    [Serializable()]
    public class Price
    {
        [XmlAttribute( "Type" )]
        public string Type { get; set; }

        [XmlAttribute( "DateFrom" )]
        public DateTime DateFrom { get; set; }

        [XmlAttribute( "DateTo" )]
        public DateTime DateTo { get; set; }

        [XmlElement( "Price" )]
        public decimal PriceValue { get; set; }

        [XmlElement( "AddPersonPrice" )]
        public decimal? AddPersonPrice { get; set; }

        [XmlElement( "PerPerson" )]
        public decimal? PerPerson { get; set; }

        [XmlElement( "Reduction2ndWeek" )]
        public decimal? Reduction2ndWeek { get; set; }
}

 [Serializable()]
    public class Object
    {
        [XmlAttribute( "id" )]
        public string id { get; set; }

        [XmlAttribute( "name" )]
        public string name { get; set; }

        [XmlElement( "Type" )]
        public int Type { get; set; }

        [XmlElement( "Persons" )]
        public int Persons { get; set; }

        [XmlElement( "Children" )]
        public int? Children { get; set; }

        [XmlElement( "Pets" )]
        public int? Pets { get; set; }

        [XmlElement( "Rooms" )]
        public int Rooms { get; set; }

        [XmlElement( "Bedrooms" )]
        public int Bedrooms { get; set; }

        [XmlElement( "Bathrooms" )]
        public int Bathrooms { get; set; }

        [XmlElement( "Size" )]
        public int? Size { get; set; }

        [XmlElement( "Stars" )]
        public int? Stars { get; set; }

        [XmlElement( "ArrivalDays" )]
        public string ArrivalDays { get; set; }

        [XmlElement( "MinOccupancy" )]
        public int? MinOccupancy { get; set; }

        [XmlElement( "MinStay" )]
        public int? MinStay { get; set; }

        [XmlElement( ElementName = "Position", Type = typeof( Position ) )]
        public Position Position { get; set; }

        [XmlElement( ElementName = "Vacancy", Type = typeof( Vacancy ) )]
        public Vacancy Vacancy { get; set; }

        [XmlElement( ElementName = "ReservationDates", Type = typeof( ReservationDates ) )]
        public ReservationDates ReservationDates { get; set; }

        [XmlElement( ElementName = "Prices", Type = typeof( Prices ) )]
        public Prices Prices { get; set; }

        .
        .
        .
    }

[Serializable()]
public class Prices
{
    [XmlElement( ElementName = "Price", Type = typeof( Price ) )]
    public Price[] PricesArray { get; set; }
}