XML 反序列化/序列化问题

Question

I am trying to implement save and load mechanic to my game. Hovewer for some reason it doesnt want to work. I keep getting the same error message : XmlException: The data at the root level is invalid. Line 1, position 1. XmlException: The data at the root level is invalid. Line 1, position 1. . Here's my code to create the serialized xml file:

 public void Save()
    {
        Save newsave = new Save();
        if (Time.timeScale == 0)
        {
            int unit_id = 0;
            GameObject[] units = new GameObject[check_number_of_units()];

            GameObject[] friendlies = GameObject.FindGameObjectsWithTag("Friend");
            GameObject[] enemyosldiers = GameObject.FindGameObjectsWithTag("Enemy");
            GameObject[] allunits = enemyosldiers.Concat(friendlies).ToArray();
            foreach (GameObject g in allunits)
            {
                Debug.Log(unit_id);
                Debug.Log(check_number_of_units());
                units[unit_id] = g;
                unit_id++;
            }
            newsave.cash = id.cash;
            newsave.enemy_cash = id.enemycash;
            newsave.units = units;
            newsave.scenename = SceneManager.GetActiveScene().name;
            FileStream file = File.Create(Application.persistentDataPath + "/gamesave.save");
            DataContractSerializer bf = new DataContractSerializer(newsave.GetType());
            MemoryStream streamer = new MemoryStream();

            bf.WriteObject(streamer, newsave);

            file.Write(streamer.GetBuffer(), 0, streamer.GetBuffer().Length);

            file.Close();
        }
    }

Here's the Save class:

[System.Serializable]
[DataContract]
public class Save
{
    [DataMember]
    public int cash;
    [DataMember]
    public int enemy_cash;
    [DataMember]
    public string scenename;
    [DataMember]
    public GameObject[] units;


}

And here's the deserialization code:

public void Load()
    {
        if (File.Exists(Application.persistentDataPath + "/gamesave.save"))
        {
            Save loadedsave = new Save();
            DataContractSerializer bf = new DataContractSerializer(loadedsave.GetType());
            FileStream file = File.Open(Application.persistentDataPath + "/gamesave.save", FileMode.Open);
            loadedsave = (Save)bf.ReadObject(file);
            file.Close();
            scene_has_been_loaded = true;
            units = loadedsave.units;
            cash = loadedsave.cash;
            enemycash = loadedsave.enemy_cash;
            SceneManager.LoadScene(loadedsave.scenename);

        }
    }

I'm lost. What makes all of this even more confusing is the fact that the error only appears when allunits[] isn't empty

Answer 1

The problem is with this line:

file.Write(streamer.GetBuffer(), 0, streamer.GetBuffer().Length);

You generally don't want to access stream's data via GetBuffer() , because it returns underlying byte array which can be larger than the data you wrote into the stream .

Either use stream.CopyTo method like this:

streamer.Seek(0, SeekOrigin.Begin); // dont forget to seek to the start of the stream
streamer.CopyTo(file);

Or simply write directly to the file, without using MemoryStream at all:

FileStream file = File.Create(Application.persistentDataPath + "/gamesave.save");
DataContractSerializer bf = new DataContractSerializer(newsave.GetType());
bf.WriteObject(file , newsave);
file.Close();

Answer 2

You colud try to create a model class for your units, thar store the properties, that are needed to reconstruct the GameObjects. I would not expect GameObject to be XmlSerializable since the XmlSerializer must know which System.Type to instanciate to fill the array. GameObject is a abstract class and therefore not instanciable.

[DataContract]
public class Unit
{
    [DataMember]
    public bool IsFriend { get; set; }
    [DataMember]
    public string Name { get; set; }
}

Answer 3

请检查您是否像为 Save 对象那样设置了GameObject 可序列化。