WP7 - XmlException - 根级别的数据无效

Question

无法弄清楚为什么我的 xml 更新在isolatedStorage 上失败，并且想知道其他人是否也遇到过类似的问题。

我试图通过迭代所有某些节点并单独更新它们来更新文件。

由于某种原因，它中途失败，然后声明数据在根级别无效，并且无效数据位于文件末尾？？？

代码如下：

我为每个练习调用 Update 方法：

    foreach (var exercise in program.Exercises)
    {
        UpdateExercise(program, exercise, true);
    }

它使用静态属性并调用数据源的 Update 方法：

    public void UpdateExercise(WorkoutProgram program, Exercise entity, bool isConversionUpdate)
    {
        ProgramDataSource.Update(program, entity, isConversionUpdate);
    }

然后调用此方法，并在这一行进行几次循环后失败： 'root = XElement .Load(XmlReader.Create(fs));'

    public void Update(WorkoutProgram program, Exercise exercise, bool isConversionUpdate)
    {
        SetupProgramSource(program);
        XElement root;

        if (!isConversionUpdate)
            exercise.ChangeDate = DateTime.Now;

        using (var store = IsolatedStorageFile.GetUserStoreForApplication())
        {
            if (!store.FileExists(_exerciseFile))
            {
                throw new NotFoundException("The file does not exist!");
            }

            using (var fs = store.OpenFile(_exerciseFile, FileMode.Open, FileAccess.Read))
            {
                root = XElement.Load(XmlReader.Create(fs));
                var element = root.Element("Exercises").Elements("Exercise").Where(e => e.Element("ID").Value.ToLower().Equals(exercise.ID.ToString().ToLower())).Single();
                element.SetElementValue("Description", exercise.Description);
                element.SetElementValue("Name", exercise.Name);
                var exerciseChanges = element.Element("ExerciseChanges");

                if (exercise is AnaerobicExercise)
                {
                    var anaerobicExercise = exercise as AnaerobicExercise;
                    element.SetElementValue("Reps", anaerobicExercise.Repetitions);
                    element.SetElementValue("Sets", anaerobicExercise.Sets);
                    element.Element("Weight").SetElementValue("Amount", anaerobicExercise.Weight.Amount);
                    element.Element("Weight").SetElementValue("Measurement", anaerobicExercise.Weight.Measurement);
                    ...                    
                }

                if (exercise is AerobicExercise)
                {
                    var aerobicExercise = exercise as AerobicExercise;
                    element.SetElementValue("Distance", aerobicExercise.Distance);
                    element.Element("Duration").SetAttributeValue("hours", aerobicExercise.Duration.Hours);
                    element.Element("Duration").SetAttributeValue("minutes", aerobicExercise.Duration.Minutes);
                    element.Element("Duration").SetAttributeValue("seconds", aerobicExercise.Duration.Seconds);
                    element.SetElementValue("Measurement", aerobicExercise.Measurement);

                    if (!isConversionUpdate)
                    {
                        var exerciseChange = exercise.Changes.OfType<AerobicExerciseChange>().FirstOrDefault(ec => ec.ChangeDate.Date == exercise.ChangeDate.Date);

                        if (exerciseChange != null)
                        {
                            var changesElement = exerciseChanges.Elements("Changes").First(x => x.Attribute("id").Value.ToLower().Equals(exerciseChange.ID.ToString().ToLower()));
                            changesElement.SetAttributeValue("hours", aerobicExercise.Duration.Hours);
                            changesElement.SetAttributeValue("minutes", aerobicExercise.Duration.Minutes);
                            changesElement.SetAttributeValue("seconds", aerobicExercise.Duration.Seconds);
                            changesElement.SetAttributeValue("distance", aerobicExercise.Distance);
                            var change = exercise.Changes.OfType<AerobicExerciseChange>().First(ec => ec.ChangeDate.Date == exercise.ChangeDate.Date);
                            change.Duration = aerobicExercise.Duration;
                            change.Distance = aerobicExercise.Distance;
                        }
                        else
                        {
                            var changeDate = new XAttribute("changeDate", string.Format("{0:dd/MM/yyyy}", aerobicExercise.ChangeDate));
                            var typeAttribute = new XAttribute("type", "Aerobic");
                            var hoursAttribute = new XAttribute("hours", aerobicExercise.Duration.Hours);
                            var minutesAttribute = new XAttribute("minutes", aerobicExercise.Duration.Minutes);
                            var secondsAttribute = new XAttribute("seconds", aerobicExercise.Duration.Seconds);
                            var distanceAttribute = new XAttribute("distance", aerobicExercise.Distance);
                            var changesElement = new XElement("Changes");
                            exerciseChange = WorkoutManagerEntityFactory.GetEntityChange<AerobicExerciseChange>();
                            var idAttribute = new XAttribute("id", exerciseChange.ID.ToString());
                            changesElement.Add(idAttribute, typeAttribute, hoursAttribute, minutesAttribute, secondsAttribute, distanceAttribute, changeDate);
                            exerciseChanges.Add(changesElement);
                            exerciseChange.ChangeDate = aerobicExercise.ChangeDate;
                            exerciseChange.Distance = aerobicExercise.Distance;
                            exerciseChange.Duration = aerobicExercise.Duration;
                            aerobicExercise.Changes.Add(exerciseChange);
                        }
                    }
                    else
                    {
                        foreach (var aerobicExerciseChange in exercise.Changes.OfType<AerobicExerciseChange>())
                        {
                            var changesElement = exerciseChanges.Elements("Changes").First(x => x.Attribute("id").Value.ToLower().Equals(aerobicExerciseChange.ID.ToString().ToLower()));
                            changesElement.SetAttributeValue("hours", aerobicExercise.Duration.Hours);
                            changesElement.SetAttributeValue("minutes", aerobicExercise.Duration.Minutes);
                            changesElement.SetAttributeValue("seconds", aerobicExercise.Duration.Seconds);
                            changesElement.SetAttributeValue("distance", aerobicExercise.Distance);
                            var change = exercise.Changes.OfType<AerobicExerciseChange>().First(ec => ec.ID == aerobicExerciseChange.ID);
                            change.Duration = aerobicExercise.Duration;
                            change.Distance = aerobicExercise.Distance;
                        }
                    }
                }
            }

            using (var fs = store.OpenFile(_exerciseFile, FileMode.Open, FileAccess.Write))
            {
                root.Save(fs);
            }
        }
    }

XML（删除了大部分练习节点的简化版本）：

<?xml version="1.0" encoding="utf-8"?>
<Program name="Strength Training">
  <ID>2eec20d2-a278-11df-bc86-00138f82a706</ID>
  <Duration hours="0" minutes="39" seconds="0" />
  <Description>Main workout program for general all over fitness</Description>
  <Exercises>
    <Exercise exerciseType="Aerobic">
      <ID>6E391E75-E75C-49CA-95FC-FEDF03D3ED1A</ID>
      <Name>Treadmill Run</Name>
      <Description>With a bar-bell on your back, feet shoulder width apart, back straight, knees slightly bent and in line with the feet, slowly go down and then back up. Squats develop power and strength.</Description>
      <Distance>4</Distance>
      <Duration hours="0" minutes="10" seconds="0" />
      <Measurement>Kilometres</Measurement>
      <ExerciseChanges>
        <Changes id="291C3CCA-9997-4B4E-A1D5-75129DBB2638" type="Aerobic" hours="0" minutes="10" seconds="0" distance="4" changeDate="27/11/2010" />
      </ExerciseChanges>
    </Exercise>
    <Exercise exerciseType="Anaerobic">
      <ID>2eec20c5-a278-11df-bc86-00138f82a706</ID>
      <Name>Squats</Name>
      <Description>With a bar-bell on your back, feet shoulder width apart, back straight, knees slightly bent and in line with the feet, slowly go down and then back up. Squats develop power and strength.</Description>
      <Reps>10</Reps>
      <Weight>
        <Amount>130</Amount>
        <Measurement>Kilograms</Measurement>
      </Weight>
      <Sets>1</Sets>
      <ExerciseChanges>
        <Changes id="D20A177E-BC23-49B0-99CD-1F467590A996" type="Anaerobic" amount="130" sets="1" reps="10" changeDate="27/11/2010" />
      </ExerciseChanges>
    </Exercise>
    <Exercise exerciseType="Anaerobic">
      <ID>2eec20d1-a278-11df-bc86-00138f82a706</ID>
      <Name>Abs</Name>
      <Description>With a bar-bell on your back, feet shoulder width apart, back straight, knees slightly bent and in line with the feet, slowly go down and then back up. Squats develop power and strength.</Description>
      <Reps>15</Reps>
      <Weight>
        <Amount>0</Amount>
        <Measurement>Kilograms</Measurement>
      </Weight>
      <Sets>1</Sets>
      <ExerciseChanges>
        <Changes id="FFF2FF28-607F-465E-8BAC-B4F21E568253" type="Anaerobic" amount="0" sets="1" reps="15" changeDate="27/11/2010" />
      </ExerciseChanges>
    </Exercise>
  </Exercises>
  <ProgramChanges>
    <Duration id="0BA96209-CF3C-4E85-8EB5-3BEE6A2DB118" hours="0" minutes="45" seconds="0" changeDate="27/11/2010" />
    <Duration id="DAEEE9DF-A155-48AC-A5CE-09D738947C76" hours="0" minutes="39" seconds="0" changeDate="28/11/2010" />
  </ProgramChanges>
</Program>

编码为 UTF-8，无 BOM。

有人以前见过这个吗？

所有的想法都值得赞赏（即使是那些说我的代码很糟糕并且需要重构的想法）。

编辑：

添加问题：InvalidOperationException - 缺少父级：

    private static XElement GetExerciseElement(Exercise entity)
    {
        var exerciseElement = new XElement("Exercise");

        if (entity is AnaerobicExercise)
        {
            var anaerobicExercise = entity as AnaerobicExercise;
            var exerciseTypeAttribute = new XAttribute("exerciseType", "Anaerobic");
            var amountElement = new XElement("Amount", anaerobicExercise.Weight.Amount);
            var measurementElement = new XElement("Measurement", anaerobicExercise.Weight.Measurement);
            var weightElement = new XElement("Weight");
            var nameElement = new XElement("Name", anaerobicExercise.Name);
            var descriptionElement = new XElement("Description", anaerobicExercise.Description);
            var repsElement = new XElement("Reps", anaerobicExercise.Repetitions);
            var setsElement = new XElement("Sets", anaerobicExercise.Sets);
            var idElement = new XElement("ID", anaerobicExercise.ID);
            var exerciseChangesElement = new XElement("ExerciseChanges");
            weightElement.Add(amountElement, measurementElement);
            var exerciseChange = new AnaerobicExerciseChange
                                     {
                                         ChangeDate = entity.ChangeDate,
                                         Amount = anaerobicExercise.Weight.Amount,
                                         Sets = anaerobicExercise.Sets,
                                         Repetitions = anaerobicExercise.Repetitions
                                     };
            entity.Changes.Add(exerciseChange);
            exerciseElement.Add(exerciseTypeAttribute, idElement, nameElement, descriptionElement, repsElement, weightElement, setsElement);
            exerciseChangesElement.ReplaceWith(GetExerciseChanges(entity, exerciseElement, exerciseChange));
            exerciseElement.Add(exerciseChangesElement);
        }

特别是这一行：

exerciseChangesElement.ReplaceWith(GetExerciseChanges(entity, exerciseElement, exerciseChange));

Answer 1

您是否在保存新版本之前删除现有文件？

如果更新后的 XML 小于原始数据，则在写入新数据时可能会留下原始数据的末尾。这将导致文件末尾出现额外的字符，从而使 XML 无效。