Working with XML in C# (.NET): Complete Guide

Working with XML in C# (.NET): Complete Guide

XML (eXtensible Markup Language) remains one of the key formats for storing and transmitting structured data in the .NET ecosystem. C# provides several powerful libraries and approaches for working with XML, from the classic XmlDocument to the modern LINQ to XML. In this article, we will cover the main tools, their features, and provide practical examples for real-world tasks.

1. Main Libraries for Working with XML in .NET

The .NET platform provides developers with several APIs for processing XML:

• System.Xml (XmlDocument, XmlReader, XmlWriter) — the classic DOM approach (Document Object Model). Allows loading the entire XML document into memory and working with it as a tree of nodes.
• LINQ to XML (XDocument, XElement, XAttribute) — a modern, lighter, and more convenient API integrated with LINQ. Recommended for most new projects.
• XmlSerializer — for automatic serialization and deserialization of C# objects to and from XML.
• XPath (SelectSingleNode, SelectNodes) — a query language for navigating an XML document. Supported in both XmlDocument and XDocument (via extensions).

2. LINQ to XML: Modern Approach

The System.Xml.Linq library (LINQ to XML) is the preferred choice for working with XML in C#. It offers clean syntax, easy loading, and support for LINQ queries.

Creating an XML Document

using System.Xml.Linq;

XDocument doc = new XDocument(    new XDeclaration("1.0", "utf-8", "yes"),    new XElement("books",        new XElement("book",            new XAttribute("id", "1"),            new XElement("title", "War and Peace"),            new XElement("author", "Leo Tolstoy"),            new XElement("price", 599.99m)        ),        new XElement("book",            new XAttribute("id", "2"),            new XElement("title", "Crime and Punishment"),            new XElement("author", "Fyodor Dostoevsky"),            new XElement("price", 450.00m)        )    ));

doc.Save("books.xml");

Loading and Reading XML

XDocument loadedDoc = XDocument.Load("books.xml");

// Get all booksvar allBooks = loadedDoc.Descendants("book");

foreach (var book in allBooks){    string id = book.Attribute("id")?.Value;    string title = book.Element("title")?.Value;    string author = book.Element("author")?.Value;    Console.WriteLine($"Book #{id}: {title} — {author}");}

LINQ Queries

// Select books more expensive than 500 rublesvar expensiveBooks = from book in loadedDoc.Descendants("book")                     where (decimal)book.Element("price") > 500                     select new                     {                         Title = (string)book.Element("title"),                         Price = (decimal)book.Element("price")                     };

foreach (var b in expensiveBooks){    Console.WriteLine($"{b.Title}: {b.Price} rub.");}

3. Classic XmlDocument

If you are working with legacy code or require full control over the DOM, use XmlDocument from the System.Xml namespace.

Loading and Navigation

using System.Xml;

XmlDocument xmlDoc = new XmlDocument();xmlDoc.Load("books.xml");

XmlNode root = xmlDoc.DocumentElement;XmlNodeList bookNodes = root.SelectNodes("book");

foreach (XmlNode node in bookNodes){    XmlNode titleNode = node.SelectSingleNode("title");    if (titleNode != null)    {        Console.WriteLine(titleNode.InnerText);    }}

Adding a New Node

XmlNode newBook = xmlDoc.Cre