我正在尝试编写一种方法来为游戏保存一些基础数据。目前，我正在尝试以xml格式保存数据，其父元素<data>元素包含<leveldata>元素数组，这些元素包含索引，完成和尝试字段。这是我第一次尝试序列化c#中的任何内容，因此我遇到了一些问题，目前，当我尝试invalidoperationexception时，它会因deserialize而失败文件（底部的例外细节）。
这是代码。
public void SaveData()
{
const string filename = "data.vision";
#if WINDOWS_PHONE
IsolatedStorageFile dataFile = IsolatedStorageFile.GetUserStoreForApplication();
#else
IsolatedStorageFile dataFile = IsolatedStorageFile.GetUserStoreForDomain();
#endif
try
{
// Create an isolated storage stream and initialize it as null.
IsolatedStorageFileStream isolatedFileStream = null;
// Open the isolated storage stream, and write the save data file.
if (dataFile.FileExists(filename))
{
using (isolatedFileStream = dataFile.OpenFile(filename, FileMode.Open, FileAccess.ReadWrite))
{
// Read the data from the file.
XmlSerializer serializer = new XmlSerializer(typeof(Data));
// Store each of the deserialized data objects in the list.
Data savedData = (Data)serializer.Deserialize(isolatedFileStream);
// Loop through the saved data objects.
for(int i = 0; i < savedData.Levels.Count; i++)
{
// Get the data object in question.
LevelData levelData = savedData.Levels[i];
// Check to see if the index of the data object corresponds to the active level index.
if (levelData.Index == mLevelIndex)
{
// Check that the attempts already saved is less.
if (levelData.Attempts < mLevel.AttemptCounter)
levelData.Attempts = mLevel.AttemptCounter;
// Check that the
if (levelData.PercentComplete < 50)
levelData.PercentComplete = 50;
}
}
serializer.Serialize(isolatedFileStream, savedData);
}
}
else
{
// If there is no data file, create a new one.
using (isolatedFileStream = dataFile.CreateFile(filename))
{
// Check the file stream has been initialized.
if (isolatedFileStream != null)
{
// Create a new data object to store the meta data for the current level.
Data data = new Data();
// Create a list to store the data already saved.
data.Levels = new List<LevelData>();
// Initialize the new data values.
LevelData levelData = new LevelData();
levelData.Index = mLevelIndex;
levelData.Attempts = mLevel.AttemptCounter;
levelData.PercentComplete = 50;
// Add the level data.
data.Levels.Add(levelData);
// Convert the object to XML data and put it in the stream.
XmlSerializer serializer = new XmlSerializer(typeof(Data));
// Seriaize the data.
serializer.Serialize(isolatedFileStream, data);
}
}
}
}
finally
{
// Dispose the storage file, in order to commit changes.
dataFile.Dispose();
}
}
DATA：
public struct Data
{
/// <summary>
/// The Level data object.
/// </summary>
[XmlArray(ElementName = "Levels")]
public List<LevelData> Levels;
}
等级数据
public struct LevelData
{
/// <summary>
/// The index of the level.
/// </summary>
[XmlElement(ElementName = "Index")]
public int Index;
/// <summary>
/// The number of attempts the player has made for a particular level.
/// </summary>
[XmlElement(ElementName = "Attempts")]
public int Attempts;
/// <summary>
/// A value describing the furthest the player has ever got within the level.
/// </summary>
[XmlElement(ElementName = "PercentComplete")]
public int PercentComplete;
}
例外细节：
{System.InvalidOperationException: There is an error in XML document (10, 10). ---> System.Xml.XmlException: Unexpected XML declaration. The XML declaration must be the first node in the document, and no white space characters are allowed to appear before it. Line 10, position 10.
at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg)
at System.Xml.XmlTextReaderImpl.ParsePI(BufferBuilder piInDtdStringBuilder)
at System.Xml.XmlTextReaderImpl.ParseDocumentContent()
at System.Xml.XmlTextReaderImpl.Read()
at System.Xml.XmlReader.ReadEndElement()
at System.Xml.Serialization.XmlSerializationReader.ReadEndElement()
at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderData.Read3_Data(Boolean checkType)
at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderData.Read4_Data()
--- End of inner exception stack trace ---
at System.Xml.Serialization.XmlSerializer.Deserialize(XmlReader xmlReader, String encodingStyle, Object events)
at System.Xml.Serialization.XmlSerializer.Deserialize(Stream stream)
at Vision.GameplayScreen.SaveData()
at Vision.GameplayScreen.HandleInput(InputState input)
at Vision.ScreenManager.Update(GameTime gameTime)
at Microsoft.Xna.Framework.Game.<.cctor>b__19(IUpdateable updateable, GameTime gameTime)
at Microsoft.Xna.Framework.Game.SortingFilteringCollection`1.ForEachFilteredItem[TUserData](Action`2 action, TUserData userData)
at Microsoft.Xna.Framework.Game.Update(GameTime gameTime)
at Vision.Game.Update(GameTime gameTime)
at Microsoft.Xna.Framework.Game.DoUpdate(GameTime gameTime)
at Microsoft.Xna.Framework.Game.Tick()
at MonoGame.Framework.WindowsPhone.SurfaceUpdateHandler.Draw(Device device, DeviceContext context, RenderTargetView renderTargetView)
at MonoGame.Framework.WindowsPhone.DrawingSurfaceUpdateHandler.DrawingSurfaceContentProvider.GetTexture(Size2F surfaceSize, DrawingSurfaceSynchronizedTexture& synchronizedTexture, RectangleF& textureSubRectangle)
at SharpDX.Direct3D11.DrawingSurfaceContentProviderShadow.DrawingSurfaceContentProviderVtbl.GetTexture(IntPtr thisPtr, IntPtr surfaceSize, IntPtr synchronizedTexture, IntPtr textureSubRectangle)}
答案 0 :(得分：1)
在读取文件之后，在反序列化之前实现它：
isolatedFileStream.Position = 0;
答案 1 :(得分：0)
序列化/反序列化的代码很好。问题必须在于您使用IsolatedStorageFileStream，特别是您正在重复使用相同的流进行读写。我建议将它分成两个功能 - 一个用于保存，一个用于加载。然后，如果文件不存在，您可以调用Load（），Edit（），Save（），或者只调用Create（）和Save（）。
另外，如上所述，发布当前存在于磁盘上的Xml会很有帮助。它似乎被负载，保存过程所破坏。
我测试了LINQPad中的序列化代码，如下所示：
void Main()
{
var xml = Save();
Console.WriteLine(xml);
var data = Load(xml);
Console.WriteLine("\r\nLevel count: " + data.Levels.Count.ToString());
}
// Define other methods and classes here
public struct LevelData
{
/// <summary>
/// The index of the level.
/// </summary>
[XmlElement(ElementName = "Index")]
public int Index;
/// <summary>
/// The number of attempts the player has made for a particular level.
/// </summary>
[XmlElement(ElementName = "Attempts")]
public int Attempts;
/// <summary>
/// A value describing the furthest the player has ever got within the level.
/// </summary>
[XmlElement(ElementName = "PercentComplete")]
public int PercentComplete;
}
public struct Data
{
/// <summary>
/// The Level data object.
/// </summary>
[XmlArray(ElementName = "Levels")]
public List<LevelData> Levels;
}
public string Save()
{
Data data = new Data();
// Create a list to store the data already saved.
data.Levels = new List<LevelData>();
// Initialize the new data values.
LevelData levelData = new LevelData();
levelData.Index = 1;
levelData.Attempts = 3;
levelData.PercentComplete = 50;
// Add the level data.
data.Levels.Add(levelData);
// Convert the object to XML data and put it in the stream.
XmlSerializer serializer = new XmlSerializer(typeof(Data));
var sb = new StringBuilder();
using (var sr = new StringWriter(sb))
{
// Seriaize the data.
serializer.Serialize(sr, data);
}
return sb.ToString();
}
public Data Load(string xml)
{
// Convert the object to XML data and put it in the stream.
XmlSerializer serializer = new XmlSerializer(typeof(Data));
using (var sr = new StringReader(xml))
{
return (Data)serializer.Deserialize(sr);
}
}