XML Serialization in C#

Introduction

XML Serialization in C# allows you to convert an object into an XML format that can be easily stored, transferred, or reconstructed later. This process is essential for persisting data, communicating with web services, or simply exchanging data between different parts of a system.

Setting Up

To start with XML Serialization in C#, you need to include the System.Xml.Serialization namespace in your project. This namespace contains the necessary classes to perform serialization and deserialization.

Basic XML Serialization

Let's begin with a simple example where we serialize and deserialize a basic object. Consider a class Person with properties Name and Age.

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

Serializing an Object

To serialize an object, you need to create an instance of the XmlSerializer class, passing the type of the object you want to serialize to its constructor. Then, use the Serialize method to convert the object to XML.

Person person = new Person { Name = "John Doe", Age = 30 };
XmlSerializer serializer = new XmlSerializer(typeof(Person));
using (StringWriter writer = new StringWriter())
{
    serializer.Serialize(writer, person);
    string xml = writer.ToString();
    Console.WriteLine(xml);
}
                

<Person xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Name>John Doe</Name>
  <Age>30</Age>
</Person>
                

Deserializing an Object

Deserialization is the process of converting XML back into an object. Use the Deserialize method of the XmlSerializer class to achieve this.

string xml = "<Person><Name>John Doe</Name><Age>30</Age></Person>";
XmlSerializer serializer = new XmlSerializer(typeof(Person));
using (StringReader reader = new StringReader(xml))
{
    Person person = (Person)serializer.Deserialize(reader);
    Console.WriteLine($"Name: {person.Name}, Age: {person.Age}");
}
                

Advanced XML Serialization

XML Serialization in C# also supports more advanced scenarios, such as serializing collections, handling namespaces, and controlling XML attributes.

Serializing Collections

You can serialize collections like lists or arrays in a similar manner. Consider a class Team that contains a list of Person objects.

public class Team
{
    public List<Person> Members { get; set; }
}
                

Serializing a Team object would include serializing all its members.

Team team = new Team
{
    Members = new List<Person>
    {
        new Person { Name = "John Doe", Age = 30 },
        new Person { Name = "Jane Doe", Age = 25 }
    }
};
XmlSerializer serializer = new XmlSerializer(typeof(Team));
using (StringWriter writer = new StringWriter())
{
    serializer.Serialize(writer, team);
    string xml = writer.ToString();
    Console.WriteLine(xml);
}
                

<Team xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Members>
    <Person>
      <Name>John Doe</Name>
      <Age>30</Age>
    </Person>
    <Person>
      <Name>Jane Doe</Name>
      <Age>25</Age>
    </Person>
  </Members>
</Team>
                

Controlling XML Format with Attributes

You can control how your class and its members are serialized by using various attributes from the System.Xml.Serialization namespace.

Example with Attributes

Consider customizing the XML output using attributes like XmlElement, XmlAttribute, and XmlIgnore.

public class Person
{
    [XmlElement("FullName")]
    public string Name { get; set; }
    
    [XmlAttribute("Age")]
    public int Age { get; set; }
    
    [XmlIgnore]
    public string Password { get; set; }
}
                

Serialized output will now reflect these customizations.

Person person = new Person { Name = "John Doe", Age = 30, Password = "secret" };
XmlSerializer serializer = new XmlSerializer(typeof(Person));
using (StringWriter writer = new StringWriter())
{
    serializer.Serialize(writer, person);
    string xml = writer.ToString();
    Console.WriteLine(xml);
}
                

<Person Age="30" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <FullName>John Doe</FullName>
</Person>