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Windows Phone 7中的DataContractSerializer问题

windows-phone-7 serialization

Carlo · 技术社区 · 14 年前

<SomeObject xmlns="someNamespace">
</SomeObject>>>

谢谢。

实际上不,这不是问题所在。这次文件很好,这就是它的样子:

<FavoriteClubManager xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/TicketingWP7.Preferences">
 <FavoriteClubs xmlns:d2p1="http://schemas.microsoft.com/2003/10/Serialization/Arrays">
  <d2p1:KeyValueOfstringboolean>
   <d2p1:Key>XXX</d2p1:Key>
   <d2p1:Value>true</d2p1:Value>
  </d2p1:KeyValueOfstringboolean>
 </FavoriteClubs>
</FavoriteClubManager>

这就是我在反序列化时遇到的错误:

但我看文件没什么问题。

保存:

using (IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication())
{
    try
    {
        using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(_fileName, FileMode.Create, file))
        {
            DataContractSerializer serializer = new DataContractSerializer(typeof(FavoriteClubManager));

            serializer.WriteObject(stream, this);
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show("There was an error saving your favorite clubs. " + ex.Message);
    }
}

加载:

using (IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication())
{
    if (file.FileExists(_fileName))
    {
        try
        {
            using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(_fileName, FileMode.Open, file))
            {
                DataContractSerializer serializer = new DataContractSerializer(typeof(FavoriteClubManager));

                FavoriteClubManager temp = serializer.ReadObject(stream) as FavoriteClubManager;

                stream.Close();
            }

            _isLoaded = true;
        }
        catch (Exception ex)
        {
            MessageBox.Show("There was an error loading your favorite clubs. " + ex.Message);
        }
    }
}

2 回复 | 直到 14 年前

Matt Lacey 14 年前

问题在于:

将对象序列化一次,然后将其保存到独立存储。
从独立存储中读取对象并将其反序列化。
您从独立存储中读取它,但由于额外的字符,无法对其进行反序列化。

如果这是重新创建问题的流程,我怀疑随后保存的seialization是一个稍小的对象,因此创建一个序列化字符串,该字符串比之前编写的字符串小。
当后面的字符串被保存时,它被写在先前保存的字符串的顶部,而旧字符串的末端仍然留在那里。

解决方案是在保存新内容之前,确保删除现有文件或删除内容。

我以前也有过类似的问题,很难发现。

顺便说一下,您可能还想重新考虑有关性能的序列化策略。看一看 this blog post by Kevin Marshall 更多信息。

Carlo 14 年前

解决了。在这件事上作弊了。我基本上是用XDocument读取XML文档,用XDocument.CreateReader()获取读取器,然后将读取器传递给DataContractSerializer。我知道这不是很优雅,但这是一个解决方案。希望我将来能想出更好的解决办法。现在,这里是代码:

private bool Load()
{
    if (!_isLoaded)
    {
        using (IsolatedStorageFile file = IsolatedStorageFile.GetUserStoreForApplication())
        {
            if (file.FileExists(_fileName))
            {
                string text = string.Empty;

                try
                {
                    using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(_fileName, FileMode.Open, file))
                    {
                        if (stream.Length > 0)
                        {
                            XDocument document = GetXDocument(stream);

                            DataContractSerializer serializer = new DataContractSerializer(typeof(ClubManager));

                            ClubManager temp = serializer.ReadObject(document.CreateReader()) as ClubManager;

                            stream.Close();
                        }
                    }

                    _isLoaded = true;
                }
                catch (Exception ex)
                {
                    MessageBox.Show("There was an error loading your favorite clubs. " + ex.Message);
                }
            }
        }
    }

    return _isLoaded;
}

private XDocument GetXDocument(IsolatedStorageFileStream stream)
{
    // read the file to find errors
    string documentText = ReadBytes(stream);

    return XDocument.Parse(documentText);
}

private static string ReadBytes(IsolatedStorageFileStream stream)
{
    byte[] buffer = new byte[stream.Length];

    stream.Read(buffer, 0, buffer.Length);

    string normal = string.Empty;
    string hex = BitConverter.ToString(buffer).Replace("-", "");

    while (hex.Length > 0)
    {
        // Use ToChar() to convert each ASCII value (two hex digits) to the actual character
        normal += System.Convert.ToChar(System.Convert.ToUInt32(hex.Substring(0, 2), 16)).ToString();
        // Remove from the hex object the converted value
        hex = hex.Substring(2, hex.Length - 2);
    }

    return normal;
}

谢谢!