有时C＃XmlSerializer序列化（保存）错误，字符数超出预期

Question

通常，您可以操作文件，效果很好，但是有时文件会出错，例如..（末尾的额外部分“ ConfigSetting>”），我所做的就是打开，编辑并保存它。

<?xml version="1.0"?>
<SystemConfigSetting xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" IsRuntime="true">
<ReportSchedulers>
<ReportScheduler ReportName="report1" FullreportName="report1" IsEnableAutosaveReport="true" Hour="14" Minute="50" Second="0" ReportSave="Daily" DayofWeek="Sunday" LastUpdate="0001-01-01T00:00:00" />
<ReportScheduler ReportName="report2" FullreportName="report2" IsEnableAutosaveReport="false" Hour="0" Minute="0" Second="0" ReportSave="Daily" DayofWeek="Sunday" LastUpdate="0001-01-01T00:00:00" />
<ReportScheduler ReportName="report3" FullreportName="report3" IsEnableAutosaveReport="false" Hour="0" Minute="0" Second="0" ReportSave="Daily" DayofWeek="Sunday" LastUpdate="0001-01-01T00:00:00" />
<ReportScheduler ReportName="report4" FullreportName="report4" IsEnableAutosaveReport="false" Hour="0" Minute="0" Second="0" ReportSave="Daily" DayofWeek="Sunday" LastUpdate="0001-01-01T00:00:00" />
<ReportScheduler ReportName="report5" FullreportName="report5" IsEnableAutosaveReport="false" Hour="0" Minute="0" Second="0" ReportSave="Daily" DayofWeek="Sunday" LastUpdate="0001-01-01T00:00:00" />
</ReportSchedulers>
</SystemConfigSetting>ConfigSetting>

除了结尾ConfigSetting>之外的其他部分是正确的，我尝试删除结尾的多余部分，并且配置文件将能够反序列化。

下面是我的代码。

保存系统配置：

public static bool SaveSystemConfig(SystemConfigSetting systemConfig)
    {
        try
        {
            XmlSerializer xmlSerializer = new XmlSerializer(typeof(SystemConfigSetting));
            using (FileStream fs = new FileStream(CONFIGFILEPATH), FileMode.Open))
            {
                xmlSerializer.Serialize(fs, systemConfig);
                fs.Close();
            }
            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }

SystemConfigSetting：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Serialization;

namespace HZSpreadSheet.Model
{
    [Serializable]
    [XmlRoot]
    public class SystemConfigSetting
    {
        private bool isRuntime = false;
        private List<ReportScheduler> reportSchedulers = new List<ReportScheduler>();
        [XmlAttribute]
        public bool IsRuntime { get => isRuntime; set => isRuntime = value; }
        [XmlArray]
        [XmlArrayItem]
        public List<ReportScheduler> ReportSchedulers { get => reportSchedulers; set => reportSchedulers = value; }
    }
}

ReportScheduler：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Serialization;

namespace HZSpreadSheet.Model
{
    public enum ReportSaveFrequency
    {
        Daily = 0,
        Weekly = 1,
        Monthly = 2,
        Manually =3
    }
    public enum DayofWeek
    {
        Sunday = 0,
        Monday = 1,
        Tuesday = 2,
        Wednesday = 3,
        Thursday = 4,
        Friday = 5,
        Saturday = 6
    }
    [XmlRoot]
    public class ReportScheduler
    {
        private string abbr_reportName;
        private string fullreportName;
        private bool isEnableAutosaveReport = false;
        private int hour = 0;
        private int minute = 0;
        private int second =0;
        private DateTime lastUpdate;
        private DayofWeek dayofWeek;
        private ReportSaveFrequency reportSaveFrequency;

        [XmlAttribute]
        public string ReportName { get => abbr_reportName; set => abbr_reportName = value; }
        [XmlAttribute]
        public string FullreportName { get => fullreportName; set => fullreportName = value; }
        [XmlAttribute]
        public bool IsEnableAutosaveReport { get => isEnableAutosaveReport; set => isEnableAutosaveReport = value; }
        [XmlAttribute]
        public int Hour { get => hour; set => hour = value; }
        [XmlAttribute]
        public int Minute { get => minute; set => minute = value; }
        [XmlAttribute]
        public int Second { get => second; set => second = value; }
        [XmlAttribute]
        public ReportSaveFrequency ReportSaveFrequency { get => reportSaveFrequency; set => reportSaveFrequency = value; }
        [XmlAttribute]
        public DayofWeek DayofWeek { get => dayofWeek; set => dayofWeek = value; }
        [XmlAttribute]
        public DateTime LastUpdate { get => lastUpdate; set => lastUpdate = value; }
    }
}

Answer 1

如果您覆盖文件（或类似的流）并用shorter数据覆盖longer文件，而不会截断它，则会发生这种情况。如果打开现有文件以便通过写入（FileMode.Open）进行随机访问，则它假定您将要编辑内容，但not并假定您只想要新位。您看到的是old有效负载中的多余字节，这些多余字节不会自动删除。截断有两种方法：

1. 打开文件时使用FileMode.Create，它将文件初始化为零长度
2. 写完后在SetLength上使用Stream，以告诉它新的长度-例如stream.SetLength(stream.Position);