A Complete Guide - XML Serialization and Deserialization in C#

Example 1: Serializing a Simple Class

Let's start with a basic class that represents a person:

using System;
using System.Xml.Serialization;
using System.IO; // Step 1: Define the class to serialize
[XmlRoot("Person")]
public class Person
{ [XmlElement("FirstName")] public string FirstName { get; set; } [XmlElement("LastName")] public string LastName { get; set; } [XmlElement("Age")] public int Age { get; set; } // Default constructor is required by XmlSerializer public Person() { // Initialization can be done here if necessary } public Person(string firstName, string lastName, int age) { this.FirstName = firstName; this.LastName = lastName; this.Age = age; }
} class Program
{ static void Main() { // Step 2: Create an instance of the class Person person = new Person("John", "Doe", 30); // Step 3: Serialize the object to XML XmlSerializer serializer = new XmlSerializer(typeof(Person)); using (StreamWriter writer = new StreamWriter("person.xml")) { serializer.Serialize(writer, person); } Console.WriteLine("Serialization completed. Check 'person.xml' for the output."); }
}

Explanation:

1. Define the Class: The Person class is defined with properties FirstName, LastName, and Age. The [XmlRoot] attribute specifies the root element name for the XML, and the [XmlElement] attributes specify the names of elements for each property.
2. Create an Instance: We create an instance of the Person class.
3. Serialize: Using the XmlSerializer, we serialize the Person object to an XML file named person.xml.

Example 2: Deserializing the XML Back to an Object

Now that we have our XML file, let's deserialize it back into a Person object:

using System;
using System.Xml.Serialization;
using System.IO; // Same class definition as above
[XmlRoot("Person")]
public class Person
{ [XmlElement("FirstName")] public string FirstName { get; set; } [XmlElement("LastName")] public string LastName { get; set; } [XmlElement("Age")] public int Age { get; set; } public Person() { // Default constructor } public Person(string firstName, string lastName, int age) { this.FirstName = firstName; this.LastName = lastName; this.Age = age; }
} class Program
{ static void Main(string[] args) { // Step 1: Deserialize the XML back to an object XmlSerializer serializer = new XmlSerializer(typeof(Person)); using (StreamReader reader = new StreamReader("person.xml")) { Person personBack = (Person)serializer.Deserialize(reader); // Step 2: Use the deserialized object Console.WriteLine($"Deserialized Person:"); Console.WriteLine($"Name: {personBack.FirstName} {personBack.LastName}"); Console.WriteLine($"Age: {personBack.Age}"); } }
}

Explanation:

1. Deserialize: We use the XmlSerializer again, but this time we call the Deserialize method to read the XML file person.xml and convert it back to a Person object.
2. Output: We print the properties of the deserialized Person object.

Example 3: Serializing and Deserializing a Collection

Next, let's consider a scenario where we want to serialize and deserialize a collection of Person objects.

using System;
using System.Collections.Generic;
using System.Xml.Serialization;
using System.IO; // Same class definition as above
[XmlRoot("Person")]
public class Person
{ [XmlElement("FirstName")] public string FirstName { get; set; } [XmlElement("LastName")] public string LastName { get; set; } [XmlElement("Age")] public int Age { get; set; } public Person() { // Default constructor } public Person(string firstName, string lastName, int age) { this.FirstName = firstName; this.LastName = lastName; this.Age = age; }
} [XmlRoot("People")]
public class PeopleList
{ [XmlElement("Person")] public List<Person> People { get; set; } = new List<Person>(); // Default constructor is required by XmlSerializer public PeopleList() {} public void AddPerson(Person person) { this.People.Add(person); }
} class Program
{ static void Main(string[] args) { // Step 1: Create a list of people PeopleList peopleList = new PeopleList(); peopleList.AddPerson(new Person("Alice", "Smith", 25)); peopleList.AddPerson(new Person("Bob", "Brown", 40)); // Step 2: Serialize the list to XML XmlSerializer serializer = new XmlSerializer(typeof(PeopleList)); using (StreamWriter writer = new StreamWriter("peoplelist.xml")) { serializer.Serialize(writer, peopleList); } Console.WriteLine("Serialization completed. Check 'peoplelist.xml' for the output."); // Step 3: Deserialize the XML back to a list of people XmlSerializer deserializeSerializer = new XmlSerializer(typeof(PeopleList)); using (StreamReader reader = new StreamReader("peoplelist.xml")) { PeopleList peopleBack = (PeopleList)deserializeSerializer.Deserialize(reader); // Step 4: Use the deserialized list Console.WriteLine("\nDeserialized People List:"); foreach (Person p in peopleBack.People) { Console.WriteLine($"Name: {p.FirstName} {p.LastName}, Age: {p.Age}"); } } }
}

Explanation:

1. Collection Class: PeopleList contains a list of Person objects. The [XmlRoot] attribute for PeopleList specifies the root of the XML. The [XmlElement] attribute inside PeopleList specifies the name of the elements containing persons.
2. Serialize: Serializes the PeopleList object to an XML file named peoplelist.xml.
3. Deserialize: Reads the XML file and converts it back to a PeopleList object.
4. Output: Iterate through and print the properties of each Person in the deserialized list.

These examples are meant to give a clear understanding of how XML serialization and deserialization work in C#. As your requirements grow, you might find it necessary to explore more advanced usage such as custom attributes, namespaces, etc., but this should form a strong starting point.