我正在 Silverlight 中构建一个 Windows Phone 7 应用程序。我在使用IsolatedStorageFile.
以下方法应该将一些数据写入文件：
private static void writeToFile(IList<Story> stories)
{
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
using (IsolatedStorageFileStream stream = storage.OpenFile(STORIES_FILE, FileMode.Append))
{
using (StreamWriter writer = new StreamWriter(stream))
{
StringBuilder toJson = new StringBuilder();
IList<StoryJson> storyJsons = (from story in stories
where !storageStories.Contains(story)
select story.ToStoryJson()).ToList();
writer.Write(JsonConvert.SerializeObject(storyJsons));
}
}
#if DEBUG
StreamReader reader = new StreamReader(storage.OpenFile(STORIES_FILE, FileMode.Open));
string contents = reader.ReadToEnd();
#endif
}
最后DEBUG是让我检查数据是否正在写入。我已经验证是这样的。此方法被调用 6 次以上。每次，都会附加更多数据。
但是，当我去读取数据时，我得到的唯一 JSON 是我在一次调用writeToFile(). 这是我的阅读方法：
private static IList<Story> storageStories;
private static IList<Story> readFromStorage()
{
if (storageStories != null)
{
return storageStories;
}
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
if (! storage.FileExists(STORIES_FILE))
{
storage.CreateFile(STORIES_FILE);
storageStories = new List<Story>();
return storageStories;
}
string contents;
using (IsolatedStorageFileStream stream = storage.OpenFile(STORIES_FILE, FileMode.OpenOrCreate))
{
using (StreamReader reader = new StreamReader(stream))
{
contents = reader.ReadToEnd();
}
}
JsonSerializer serializer = new JsonSerializer();
storageStories = JArray.Parse(contents).Select(storyData => storyOfJson(serializer, storyData)).ToList();
return storageStories;
}
我在这里做错了什么？我是否错误地写入文件？我很确定唯一能够读回的数据来自第一次写入。
更新：我添加了两个Flush()调用，但它崩溃了：
private static void writeToFile(IList<Story> stories)
{
IsolatedStorageFile storage = IsolatedStorageFile.GetUserStoreForApplication();
using (IsolatedStorageFileStream stream = storage.OpenFile(STORIES_FILE, FileMode.Append))
{
using (StreamWriter writer = new StreamWriter(stream))
{
StringBuilder toJson = new StringBuilder();
IList<StoryJson> storyJsons = (from story in stories
where !storageStories.Contains(story)
select story.ToStoryJson()).ToList();
writer.Write(JsonConvert.SerializeObject(storyJsons));
writer.Flush();
}
// FAILS
// "Cannot access a closed file." {System.ObjectDisposedException}
stream.Flush();
}
}
如果我注释掉stream.Flush()but leave writer.Flush()，我也会遇到同样的问题。
更新 2：我添加了一些打印语句。看起来一切都在序列化：
Serializing for VID 43
Serializing for VID 17
Serializing for VID 6
Serializing for VID 33
Serializing for VID 4
Serializing for VID 5
Serializing for VID 3
但实际上只有第一组被回读：
Deserializing stories with vid: 43
我已经运行了几次测试。我很确定只有第一项被回读。