Xml 简单序列化和返序列化

结构体和类都能进行 xml 的序列化和反序列化。

必须包含的命名空间：

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

基本的序列化

这里以结构体类型为例 ：

public struct Student
{
    public string Name;
    public int Age;

    public Student(string name, int age)
    {
        this.Name = name;
        this.Age = age;
    }
}

这里访问类型必须要public。

class XmlSerializerHelper
{
    public void XmlSerial(object obj, string xmlFile)
    {
        // 序列化
        using (MemoryStream ms = new MemoryStream())
        {
            XmlWriterSettings setting = new XmlWriterSettings() {
                Encoding = new UTF8Encoding(false),
                Indent = true,
            };
            using (XmlWriter writer = XmlWriter.Create(ms, setting))
            {
                XmlSerializer xmlSerializer = new XmlSerializer(obj.GetType());
                // 去掉命名空间
                XmlSerializerNamespaces ns = new XmlSerializerNamespaces();
                ns.Add("", ""); // 命名空间赋值为空
                xmlSerializer.Serialize(writer, obj, ns);

                // 用StreamWriter 
                string xmlContent = Encoding.UTF8.GetString(ms.ToArray()); // 转成字符转
                StreamWriter streamWriter = new StreamWriter(xmlFile);
                streamWriter.Write(xmlContent);
                streamWriter.Close();
            }
        }
    }

    // 返序列化
    public  object XmlDeserial(object obj, string xmlFile)
    {
        // 用 MemoryStream
        string xmlString = File.ReadAllText(xmlFile); // xml 内容提取出来
        using (MemoryStream MS = new MemoryStream(Encoding.UTF8.GetBytes(xmlString)))
        {
            using (XmlReader xr = XmlReader.Create(MS))
            {
                XmlSerializer xmlSerializer = new XmlSerializer(obj.GetType());
                obj = xmlSerializer.Deserialize(xr);  // 不要误写为 MS 流，有这个重载不会报错。但运行有错。
            }
        }          

        return obj;
    }
}

class Program
{
    static void Main(string[] args)
    {
        Student student = new Student() { Name = "毛泽东", Age = 18 };

        XmlSerializerHelper xmlSerializerHelper = new XmlSerializerHelper();
        xmlSerializerHelper.XmlSerial(student, "Student.xml");

        Console.ReadKey();
    }
}

输出，没什么问题：

<?xml version="1.0" encoding="utf-8"?>
<Student>
  <Name>毛泽东</Name>
  <Age>18</Age>
</Student>

简单反序列化

class Program
{
    static void Main(string[] args)
    {
        XmlSerializerHelper xmlSerializerHelper = new XmlSerializerHelper();

        Student stu;
        stu = (Student)xmlSerializerHelper.XmlDeserial(new Student(), "Student.xml");
        Console.WriteLine("Name = {0}\nAge = {1}", stu.Name, stu.Age);

        Console.ReadKey();
    }
}

输出，没什么问题：

Name = 毛泽东
Age = 18

测试一下嵌套序列化

public struct Student
{
    public string Name;
    public int Age;

    public OtherInfo OtherInfo;        
}
public struct OtherInfo
{
    public int Birth;
    public string Alisa;
}

class Program
{
    static void Main(string[] args)
    {
        OtherInfo otherInfo = new OtherInfo() { Birth = 1893, Alisa = "毛润之"};
        Student student = new Student() { Name = "毛泽东", Age = 18, OtherInfo = otherInfo };

        XmlSerializerHelper xmlSerializerHelper = new XmlSerializerHelper();
        xmlSerializerHelper.XmlSerial(student, "Student.xml");

        Console.ReadKey();
    }
}

输出：

<?xml version="1.0" encoding="utf-8"?>
<Student>
  <Name>毛泽东</Name>
  <Age>18</Age>
  <OtherInfo>
    <Birth>1893</Birth>
    <Alisa>毛润之</Alisa>
  </OtherInfo>
</Student>

测试下如果引用变量为null的情况

class Program
{
    static void Main(string[] args)
    {
        Student student = new Student() ;

        XmlSerializerHelper xmlSerializerHelper = new XmlSerializerHelper();
        xmlSerializerHelper.XmlSerial(student, "Student.xml");

        Console.ReadKey();
    }
}

输出：

<?xml version="1.0" encoding="utf-8"?>
<Student>
  <Age>0</Age>
  <OtherInfo>
    <Birth>0</Birth>
  </OtherInfo>
</Student>

可见，null值不进行序列化，int类型会默认为0，所以存在。

把struct改成class：

public class Student
{
    public string Name;
    public int Age;

    public OtherInfo OtherInfo;        
}
public class OtherInfo
{
    public int Birth;
    public string Alisa;
}

输出：

<?xml version="1.0" encoding="utf-8"?>
<Student>
  <Age>0</Age>
</Student>

class为引用类型，为 null 没输出了。

数组的序列化

输出：

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string Sex { get; set; }

    [XmlElement("Dog")] // 不要“再包一层”
    public List<Dog> Dog { get; set; }

    public string Good { get; set; } = "100";
    private string valuePrivate { get; set; } = "0";
}

public class Dog
{
    public string Name { get; set; }
    public int Age { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        List<Dog> dogs = new List<Dog> {
            new Dog() { Name = "小黑", Age = 9 },
            new Dog() { Name = "小黄", Age = 10 }
        };

        Person person = new Person() {
            Name = "孙悟空",
            Age = 500,
            Sex = "男",
            Dog = dogs
        };

        XmlSerializerHelper xmlSerializerHelper = new XmlSerializerHelper();
        xmlSerializerHelper.XmlSerial(person, "Person.xml");

        Console.ReadKey();
    }
}

<?xml version="1.0" encoding="utf-8"?>
<Person>
  <Name>孙悟空</Name>
  <Age>500</Age>
  <Sex>男</Sex>
  <Dog>
    <Name>小黑</Name>
    <Age>9</Age>
  </Dog>
  <Dog>
    <Name>小黄</Name>
    <Age>10</Age>
  </Dog>
  <Good>100</Good>
</Person>

可见：

1. 数组如果不要再包一层，[XmlElement("Dog")] // 不要“再包一层”显示的命名个节点。不然输出如下：

<?xml version="1.0" encoding="utf-8"?>
<Person>
  <Name>孙悟空</Name>
  <Age>500</Age>
  <Sex>男</Sex>
  <Dog>
    <Dog>
      <Name>小黑</Name>
      <Age>9</Age>
    </Dog>
    <Dog>
      <Name>小黄</Name>
      <Age>10</Age>
    </Dog>
  </Dog>
  <Good>100</Good>
</Person>

Dog 数组外面包了一层<Dog>。

2. private string valuePrivate { get; set; } = "0";私有成员没有被序列化。

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参考：
https://www.cnblogs.com/guogangj/p/7489218.html