将实体类或者集合序列化为xml（xmlDataDocument）

/// <summary>
/// 将数据序列化为Xml
/// </summary>
/// <param name="oType">被序列化的数据类型（实体类类型或者集合类型，如果为集合类型则不要使用该集合类型的接口类型）</param>
/// <param name="oData">数据对象</param>
/// <returns></returns>
private XmlDataDocument SerialiazerXmlDataDoc(Type oType, object oData)
{
XmlSerializer oXmlSerializer = new XmlSerializer(oType); //为序列化器指定序列化类型
MemoryStream oMemStream = new MemoryStream();

oXmlSerializer.Serialize(oMemStream, oData); //为序列化器指定要被序列化的数据

XmlDataDocument oXmlDataDoc = new XmlDataDocument();
oXmlDataDoc.LoadXml(System.Text.Encoding.UTF8.GetString(oMemStream.ToArray()));

//将序列化的结果，转换为字符串加载进xmldatadocument对象

return oXmlDataDoc;
}