Linq to XML - update/alter the nodes of an XML Document

Question

I\'ve got 2 Questions:

1. I\'ve sarted working around with Linq to XML and i\'m wondering if it is possible to change an XML document via Linq. I mean, is there some

Answer 1

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Xml.Linq; //using System.Xml;

namespace XMLtoLinqApp { class Program { static void Main(string[] args) {

        //XmlDocument doc = new XmlDocument();
        //XmlElement newBook=doc.CreateElement("BookParticipant");
        //newBook.SetAttribute("Author");

        //Using Functional Construction to Create an XML Schema
        XElement xBookParticipant = new XElement("BookParticipant",
                                        new XElement("FirstName", "Joe"),
                                        new XElement("LastName", "Rattz"));
        Console.WriteLine(xBookParticipant.ToString());


        //Creates the Same XML Tree as Listing 6-1 but with Far Less Code
        XElement xBookParticipants = new XElement("BookParticipants",
                                        new XElement("BookParticipant",
                                        new XAttribute("type", "Author"),
                                        new XElement("FirstName", "Joe"),
                                        new XElement("LastName", "Rattz")),
                                        new XElement("BookParticipant",
                                        new XAttribute("type", "Editor"),
                                        new XElement("FirstName", "Ewan"),
                                        new XElement("LastName", "Buckingham")));
        Console.WriteLine(xBookParticipants.ToString());


        //-- Disadvatages of XML document
        //System.Xml.XmlElement xmlBookParticipant = new System.Xml.XmlElement("BookParticipant");
        XElement xeBookParticipant = new XElement("BookParticipant");


        XDocument xDocument = new XDocument(new XElement("BookParticipants",
                                            new XElement("BookParticipant",
                                            new XAttribute("type", "Author"),
                                            new XElement("FirstName", "Joe"),
                                            new XElement("LastName", "Rattz"))));
        Console.WriteLine(xDocument.ToString());


        //--Calling the ToString Method on an Element Produces the XML Tree
        XElement name = new XElement("Name", "Joe");
        Console.WriteLine(name.ToString());

        //--Console.WriteLine Implicitly Calling the ToString Method on an Element to Produce an XML Tree


        XElement name1 = new XElement("Person",
                                      new XElement("FirstName", "Joe"),
                                      new XElement("LastName", "Rattz"));
        Console.WriteLine(name1);

        //-- Casting an Element to Its Value’s Data Type Outputs the Value
        Console.WriteLine(name);
        Console.WriteLine((string)name);

        //--Different Node Value Types Retrieved via Casting to the Node Value’s Type
        XElement count = new XElement("Count", 12);
        Console.WriteLine(count);
        Console.WriteLine((int)count);

        XElement smoker = new XElement("Smoker", false);
        Console.WriteLine(smoker);
        Console.WriteLine((bool)smoker);

        XElement pi = new XElement("Pi", 3.1415926535);
        Console.WriteLine(pi);
        Console.WriteLine((double)pi);


        DeferredQryProblem();


        GenerateXMlFromLinqQry();

        WithoutReaching();

        Ancestors();


        AncestorsAndSelf();

        SortSample();

        FindElementwithSpecificChild();

    }

    private static void DeferredQryProblem()
    {
        XDocument xDocument = new XDocument(
                    new XElement("BookParticipants",
                    new XElement("BookParticipant",
                    new XAttribute("type", "Author"),
                    new XElement("FirstName", "Joe"),
                    new XElement("LastName", "Rattz")),
                    new XElement("BookParticipant",
                    new XAttribute("type", "Editor"),
                    new XElement("FirstName", "Ewan"),
                    new XElement("LastName", "Buckingham"))));
        IEnumerable elements =
        xDocument.Element("BookParticipants").Elements("BookParticipant");
        foreach (XElement element in elements)
        {
            Console.WriteLine("Source element: {0} : value = {1}",
            element.Name, element.Value);
        }
        foreach (XElement element in elements)
        {
            Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
            element.Remove();
        }
        Console.WriteLine(xDocument);


        foreach (XElement element in elements)
        {
            Console.WriteLine("Source element: {0} : value = {1}",
            element.Name, element.Value);
        }
        foreach (XElement element in elements.ToArray())
        {
            Console.WriteLine("Removing {0} = {1} ...", element.Name, element.Value);
            element.Remove();
        }
        Console.WriteLine(xDocument);
    }

    //-- Creating an Attribute and Adding It to Its Element
    private static void CreatingAttribute()
    {
        XElement xBookParticipant = new XElement("BookParticipant", new XAttribute("type", "Author"));
        Console.WriteLine(xBookParticipant);
    }

    //--Creating a Comment with Functional Construction
    private static void CreatingComment()
    {
        XElement xBookParticipant = new XElement("BookParticipant",
                                                  new XComment("This person is retired."));
        Console.WriteLine(xBookParticipant);
    }

    //--Creating a Declaration with Functional Construction
    private static void CreateXmlDeclaration()
    {
        XDocument xDocument = new XDocument(new XDeclaration("1.0", "UTF-8", "yes"),

new XElement("BookParticipant")); Console.WriteLine(xDocument); }

    private static void GenerateXMlFromLinqQry()
    {
        BookParticipant[] bookParticipants = new[] {new BookParticipant {FirstName = "Joe", LastName = "Rattz",
                                                    ParticipantType = ParticipantTypes.Author},
                                                    new BookParticipant {FirstName = "Ewan", LastName = "Buckingham",
                                                    ParticipantType = ParticipantTypes.Editor}
                                                    };
        XElement xBookParticipants =
        new XElement("BookParticipants",
                     bookParticipants.Select(p =>
                new XElement("BookParticipant",
                new XAttribute("type", p.ParticipantType),
                new XElement("FirstName", p.FirstName),
                new XElement("LastName", p.LastName))));


        Console.WriteLine(xBookParticipants);
    }

    //-- Obtaining Elements Without Reaching
    private static void WithoutReaching()
    {
        XDocument xDocument = new XDocument(new XElement("BookParticipants",
                                            new XElement("BookParticipant",
                                            new XAttribute("type", "Author"),
                                            new XElement("FirstName", "Joe"),
                                            new XElement("LastName", "Rattz")),
                                            new XElement("BookParticipant",
                                            new XAttribute("type", "Editor"),
                                            new XElement("FirstName", "Ewan"),
                                            new XElement("LastName", "Buckingham"))));

        //-- Simple Descendants
        IEnumerable elements = xDocument.Descendants("BookParticipant");


        foreach (XElement element in elements)
        {
            Console.WriteLine("Element: {0} : value = {1}",
            element.Name, element.Value);
        }


        //-- Descendants with Where Clause
        IEnumerable elements1 = xDocument.Descendants("BookParticipant")
                                                   .Where(e => ((string)e.Element("FirstName")) == "Ewan");
        foreach (XElement element1 in elements1)
        {
            Console.WriteLine("Element: {0} : value = {1}",
            element1.Name, element1.Value);
        }

    }


    //-- Ancestors Prototype
    private static void Ancestors()
    {
        XDocument xDocument = new XDocument(new XElement("BookParticipants",
                                            new XElement("BookParticipant",
                                            new XAttribute("type", "Author"),
                                            new XElement("FirstName", "Joe"),
                                            new XElement("LastName", "Rattz")),
                                            new XElement("BookParticipant",
                                            new XAttribute("type", "Editor"),
                                            new XElement("FirstName", "Ewan"),
                                            new XElement("LastName", "Buckingham"))));

        IEnumerable elements = xDocument.Element("BookParticipants").Descendants("FirstName");
        // First, I will display the source elements.
        foreach (XElement element in elements)
        {
            Console.WriteLine("Source element: {0} : value = {1}",
            element.Name, element.Value);
        }
        // Now, I will display the ancestor elements for each source element.
        foreach (XElement element in elements.Ancestors())
        {
            Console.WriteLine("Ancestor element: {0}", element.Name);
        }


        // Now, I will display the ancestor elements for each source element.
        foreach (XElement element in elements.Ancestors("BookParticipant"))
        {
            Console.WriteLine("Ancestor element: {0}", element.Name);
        }

    }


    //-- AncestorsAndSelf
    private static void AncestorsAndSelf()
    {
        XDocument xDocument = new XDocument(
            new XElement("BookParticipants",
            new XElement("BookParticipant",
            new XAttribute("type", "Author"),
            new XElement("FirstName", "Joe"),
            new XElement("LastName", "Rattz")),
            new XElement("BookParticipant",
            new XAttribute("type", "Editor"),
            new XElement("FirstName", "Ewan"),
            new XElement("LastName", "Buckingham"))));
        IEnumerable elements =
        xDocument.Element("BookParticipants").Descendants("FirstName");
        // First, I will display the source elements.
        foreach (XElement element in elements)
        {
            Console.WriteLine("Source element: {0} : value = {1}",
            element.Name, element.Value);
        }
        // Now, I will display the ancestor elements for each source element.
        foreach (XElement element in elements.AncestorsAndSelf())
        {
            Console.WriteLine("Ancestor element: {0}", element.Name);
        }


        // Now, I will display the ancestor elements for each source element.
        foreach (XElement element in elements.AncestorsAndSelf("BookParticipant"))
        {
            Console.WriteLine("Ancestor element: {0}", element.Name);
        }

    }


    //-- Sort Smaple

    private static void SortSample()
    {
        XElement root = XElement.Load("Data.xml");
        IEnumerable prices =
            from el in root.Elements("Data")
            let price = (decimal)el.Element("Price")
            orderby price
            select price;
        foreach (decimal el in prices)
            Console.WriteLine(el);
    }

    //-- Find an Element with a Specific Child 
    private static void FindElementwithSpecificChild()
    {
        XElement root = XElement.Load("data.xml");
        IEnumerable tests =
            from el in root.Elements("Data")
            where (int)el.Element("Quantity") > 3
            select el;
        foreach (XElement el in tests)
            Console.WriteLine((string)el.Attribute("TestId");
    }
}

}

http://msdn.microsoft.com/en-us/library/bb387053.aspx

7.25--> A 3 24.50 B 1 89.99 A 5 4.95 A 3 66.00 B 10 .99 A 15 29.00 B 8 6.99