C#XML值不能为空。参数名称：值[重复]

Question

我做了一个自动加载用户设置xml文件的程序，但一个问题是，当我在代码中添加新值时，程序试图读取没有“data5”值的xml文件时，程序返回一个错误：

当我关闭程序时，我得到了另一个关于另一个进程使用的文件的错误

An unhandled exception of type 'System.IO.IOException' occurred in mscorlib.dll

Additional information: The process cannot access the file 'C:\Users\xxxxx\AppData\Local\APK Easy Tool\cfg.xml' because it is being used by another process.

我不明白为什么文件仍然被锁定。它应该在read.close()；之后关闭。我试图让程序在读取xml之前创建一个新的xml值，但这不是一个好主意，因为它将替换修改后的值。这是我的密码

docs = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData) + @"\APK";

if (File.Exists(docs + @"\cfg.xml"))
            {
                try
                {
                    XmlSerializer xs = new XmlSerializer(typeof(Data));
                    FileStream read = new FileStream(docs + @"\cfg.xml", FileMode.Open, FileAccess.Read, FileShare.Read);
                    Data info = (Data)xs.Deserialize(read);
                    signApkCheckBox.Checked = bool.Parse(info.Data1);
                    pathOfApk.Text = info.Data2;
                    pathOfDec.Text = info.Data3;
                    pathOfCom.Text = info.Data4;
                    disableDebugChkBox.Checked = bool.Parse(info.Data5);
                    read.Close();             
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }

private void ApkForm_FormClosed(object sender, FormClosedEventArgs e)
{
    /*
    Properties.Settings.Default.textBoxDec = pathOfDec.Text;
    Properties.Settings.Default.textBoxCom = pathOfCom.Text;
    Properties.Settings.Default.textBoxSelApk = pathOfApk.Text;
    Properties.Settings.Default.checkSignApk = signApkCheckBox.Checked;
    Properties.Settings.Default.Save();
    */

    Data info = new Data();
    info.Data1 = signApkCheckBox.Checked.ToString();
    info.Data2 = pathOfApk.Text;
    info.Data3 = pathOfDec.Text;
    info.Data4 = pathOfCom.Text;
    info.Data5 = disableDebugChkBox.Checked.ToString();
    SaveXML.SaveData(info, docs + @"\cfg.xml");
}

using System.Xml.Serialization;
using System.IO;

namespace APK
{
    public class SaveXML
    {
        public static void SaveData(object obj, string filename)
        {
            XmlSerializer sr = new XmlSerializer(obj.GetType());
            TextWriter writer = new StreamWriter(filename);
            sr.Serialize(writer, obj);
            writer.Close();
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace APK
{
    public class Data
    {
        private string data1, data2, data3, data4, data5;

        public string Data1
        {
            get { return data1; }
            set { data1 = value; }
        }

        public string Data2
        {
            get { return data2; }
            set { data2 = value; }
        }

        public string Data3
        {
            get { return data3; }
            set { data3 = value; }
        }

        public string Data4
        {
            get { return data4; }
            set { data4 = value; }
        }

        public string Data5
        {
            get { return data5; }
            set { data5 = value; }
        }
    }
}

Answer 1

也许这不能解决问题，但在read.close()；之前，将read.endread()；放入或只是尝试在catch语句上关闭它。但如前所述,最好的选择是这样做：

if (File.Exists(docs + @"\cfg.xml"))
            {
                try
                {
                    using (FileStream read = new FileStream(docs + @"\cfg.xml", FileMode.Open, FileAccess.Read, FileShare.Read)){
                        XmlSerializer xs = new XmlSerializer(typeof(Data));
                        Data info = (Data)xs.Deserialize(read);
                        signApkCheckBox.Checked = bool.Parse(info.Data1);
                        pathOfApk.Text = info.Data2;
                        pathOfDec.Text = info.Data3;
                        pathOfCom.Text = info.Data4;
                        disableDebugChkBox.Checked = bool.Parse(info.Data5);            
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }

这样你就不需要担心关闭文件了，它是“自动”完成的。