在 Root 下保存 XML 数据

Question

我正在尝试将多个条目保存到现有的 xml 文档中。但我没有得到想要的结果。我有以下代码：public static void recordScore(ScoreModel scoreModel)        {            var path = "../../Media/Leaderboard/Leaderboard.xml";            var saveModel = new LeaderboardModel();            Stream fs = new FileStream(path, FileMode.Open);            XmlReader reader = new XmlTextReader(fs);            XmlSerializer serializer = new XmlSerializer(typeof(LeaderboardModel));            if (serializer.CanDeserialize(reader))            {                LeaderboardModel o = (LeaderboardModel) serializer.Deserialize(reader);                saveModel.ScoreModels.AddRange(o.ScoreModels);            }            fs.Close();            saveModel.ScoreModels.Add(scoreModel);            System.Xml.Serialization.XmlSerializer writer =                new System.Xml.Serialization.XmlSerializer(typeof(LeaderboardModel));            System.IO.FileStream file = System.IO.File.Open(path, System.IO.FileMode.Append);            writer.Serialize(file, saveModel);            file.Close();        }我在xml文件中的输出如下：<?xml version="1.0"?><LeaderboardModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">  <ScoreModels>    <ScoreModel>      <Name>Test</Name>      <GameSpeed>Normal</GameSpeed>      <Score>11</Score>    </ScoreModel>  </ScoreModels></LeaderboardModel><?xml version="1.0"?><LeaderboardModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">  <ScoreModels>    <ScoreModel>      <Name>Test</Name>      <GameSpeed>Normal</GameSpeed>      <Score>11</Score>    </ScoreModel>  </ScoreModels>如您所见，它每次都输出 LeaderboardModel 和 ScoreModels。它应该只写一次，然后在该根下添加新的 ScoreModel。