Reading and writing an existing xml file c# 3.0 / .net3.5

Question

I have a xml-file which I want to read. How can I do it? I would not load whole xml file at runtime

(XmlDocument _xd = XmlDocument.Load(path)) 

I want to do it with Readers, but I can not achieve with it.

At the same time I want to add nodes to this xml-file with writers. How do these work with XDocument or at c# 3.5.

Kind Regards.

Answer 1

Didn't you consider also using LINQ? Like this (just pseudo-like, you would have to look it up on the web, but just to have an idea).

XDocument xmlDoc = //load or parse with XDocument.Load(..) or XDocument.Parse(...)

List<MyObject> myObj = (from myObject in xmlDoc.Descendants("myObjectTag")
                        select new MyObject
                        {
                            Name = (string)myObject.Attribute("name"),
                            ...
                        }
                        ).toList<MyObject>();

Voilà, here's a blog post I just found by quickly googling: * click *

Answer 2

Here is an example of loading xml file with XDocument, adding a child node and saving it to the use :

// Load XML file : 
XDocument xdoc = XDocument.Load(path);

// Parse XML : 
//XDocument xdoc = XDocument.Parse("<YourRootElement><ChildElement>Child 1</ChildElement></YourRootElement>");


// Add Child Node to loaded xml : 
xdoc.Element("YourRootElement").Add(
     new XElement("ChildElement", "Child 2"));

// Save XML to file : 
xdoc.Save(path);

EDIT : Use XDocument.Parse method to load XML from memory.

Answer 3

I think this is useful.

Here's an example:

using System;
using System.Xml;
namespace ReadXml1
{
    class Class1
    {
        static void Main(string[] args)
        {
            // Create an isntance of XmlTextReader and call Read method to read the file
            XmlTextReader textReader = new XmlTextReader("C:\\books.xml");
            textReader.Read();
            // If the node has value
            while (textReader.Read())
            {
                // Move to fist element
                textReader.MoveToElement();
                Console.WriteLine("XmlTextReader Properties Test");
                Console.WriteLine("===================");
                // Read this element's properties and display them on console
                Console.WriteLine("Name:" + textReader.Name);
                Console.WriteLine("Base URI:" + textReader.BaseURI);
                Console.WriteLine("Local Name:" + textReader.LocalName);
                Console.WriteLine("Attribute Count:" + textReader.AttributeCount.ToString());
                Console.WriteLine("Depth:" + textReader.Depth.ToString());
                Console.WriteLine("Line Number:" + textReader.LineNumber.ToString());
                Console.WriteLine("Node Type:" + textReader.NodeType.ToString());
                Console.WriteLine("Attribute Count:" + textReader.Value.ToString());
            }
        }
    }
}

And here's an example for XMLWriters:

using System.Xml;

class Program
{
    class Employee
    {
        int _id;
        string _firstName;
        string _lastName;
        int _salary;
        public Employee(int id, string firstName, string lastName, int salary)
        {
            this._id = id;
            this._firstName = firstName;
            this._lastName = lastName;
            this._salary = salary;
        }
        public int Id { get { return _id; } }
        public string FirstName { get { return _firstName; } }
        public string LastName { get { return _lastName; } }
        public int Salary { get { return _salary; } }
    }

    static void Main()
    {
        Employee[] employees = new Employee[4];
        employees[0] = new Employee(1, "David", "Smith", 10000);
        employees[1] = new Employee(3, "Mark", "Drinkwater", 30000);
        employees[2] = new Employee(4, "Norah", "Miller", 20000);
        employees[3] = new Employee(12, "Cecil", "Walker", 120000);

        using (XmlWriter writer = XmlWriter.Create("employees.xml"))
        {
            writer.WriteStartDocument();
            writer.WriteStartElement("Employees");

            foreach (Employee employee in employees)
            {
                writer.WriteStartElement("Employee");

                writer.WriteElementString("ID", employee.Id.ToString());
                writer.WriteElementString("FirstName", employee.FirstName);
                writer.WriteElementString("LastName", employee.LastName);
                writer.WriteElementString("Salary", employee.Salary.ToString());

                writer.WriteEndElement();
            }

            writer.WriteEndElement();
            writer.WriteEndDocument();
        }
    }
}