Xml序列化程序访问被拒绝

    public void SerializeObject(string filename, T data)
    {
        // Get the path of the save game
        string fullpath = filename;
        // Open the file, creating it if necessary
        //if (container.FileExists(filename))
        //    container.DeleteFile(filename);
        FileStream stream = (FileStream)File.Open(fullpath, FileMode.OpenOrCreate);
        try
        {
            // Convert the object to XML data and put it in the stream
            XmlSerializer serializer = new XmlSerializer(typeof(T));
            serializer.Serialize(stream, data); //Thrown HERE
        }
        finally
        {
            // Close the file
            stream.Close();
        }
    }

如何使上面的代码停止抛出无效操作异常？

完整的错误消息是：无法生成临时类 (结果 = 1(。错误 CS0016：无法写入输出文件 'c：''Users[MYUSERNAME]''AppData''Local''Temp''czdgjjs0.dll' -- '访问被拒绝。

我不知道如何解决此错误。

我正在尝试序列化我的 Level 类，如下所示：

[Serializable]
public class Level : ISerializable
{
    public string Name { get; set; }
    public int BestTime { get; set; } //In seconds
    public List<Block> levelBlocks { get; set; }
    public int Width { get; set; }
    public int Height { get; set; }
    public Level()
    {
    }
    public Level(SerializationInfo info, StreamingContext ctxt)
    {
        this.Name = (String)info.GetValue("Name", typeof(String));
        this.BestTime = (int)info.GetValue("BestTime", typeof(int));
        this.levelBlocks = (List<Block>)info.GetValue("Blocks", typeof(List<Block>));
        this.Width = (int)info.GetValue("Width", typeof(int));
        this.Height = (int)info.GetValue("Height", typeof(int));
    }
    public void GetObjectData(SerializationInfo info, StreamingContext ctxt)
    {
        info.AddValue("Name", this.Name);
        info.AddValue("BestTime", this.BestTime);
        info.AddValue("Blocks", this.levelBlocks);
        info.AddValue("Width", this.Width);
        info.AddValue("Height", this.Height);
    }
}

我的块类以类似的方式实现，并且仅保存保存的位置向量。

下面是我的保存方法：

    public static void Save()
    {
        string filename = "saved.xml";
        Level toSave = new Level();
        toSave.levelBlocks = new List<Block>();
        //TODO: build toSave
        toSave.Name = "This is a level!";
        toSave.BestTime = 0;
        foreach (Entity e in EntityController.Entities)
        {
            if (e is Block)
            {
                toSave.levelBlocks.Add((Block)e);
                if (e.Position.X > toSave.Width)
                    toSave.Width = (int)e.Position.X;
                if (e.Position.Y > toSave.Height)
                    toSave.Height = (int)e.Position.Y;
            }
        }
        serializer.SerializeObject(filename, toSave);
    }

我的程序是一个XNA游戏。