CSharp - Using SetElementValue to Update, Add, and Delete Child Elements

Introduction

SetElementValue method will only affect the first child element it finds with the specified name.

Any subsequent elements with the same name will not be affected.

Demo

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

class Program//from   w w w. ja v  a  2s.com
{
    static void Main(string[] args){
        //  we will use this to store a reference to one of the elements in the XML tree.
        XElement firstParticipant;
        
        XDocument xDocument = new XDocument(
          new XElement("Books", firstParticipant =
            new XElement("Book",
              new XAttribute("type", "Author"),
              new XElement("FirstName", "Joe"),
              new XElement("LastName", "Ruby"))));
        
        Console.WriteLine(System.Environment.NewLine + "Before updating elements:");
        Console.WriteLine(xDocument);
        
        //  First, we will use XElement.SetElementValue to update the value of an element.
        //  Since an element named FirstName is there, its value will be updated to Joseph.
        
              firstParticipant.SetElementValue("FirstName", "Joseph");
        
              //  Second, we will use XElement.SetElementValue to add an element.
              //  Since no element named MiddleInitial exists, one will be added.
              firstParticipant.SetElementValue("MiddleInitial", "C");
        
              //  Third, we will use XElement.SetElementValue to remove an element.
              //  Setting an element's value to null will remove it.
              firstParticipant.SetElementValue("LastName", null);
        
              Console.WriteLine(System.Environment.NewLine + "After updating elements:");
              Console.WriteLine(xDocument);
    }
}

Result

Related Topic

• Creating Elements with XElement
• Creating XElement from String value
• Creating XML Tree via XElement
• Creating XElement from LINQ statement
• Creating an Element and Assigning a String As Its Value
• Cast XElement to String
• Cast XElement to the Node Value's Type
• Cast a Node to a Different Data Type Than Its Value's Original Data Type
• Cast to a Bool Calls the System.Xml.XmlConvert.ToBoolean Method
• Use ToString Method on an Element to get XML Tree in String
• Creating a Text Node and Passing It As the Value of a Created Element
• Using Functional Construction to Create an XML
• Generating an XML Tree with a LINQ Query
• Deferred Execution of the XML Tree Construction by Using the XStreamingElement Class
• Accessing Named Child Elements Using the Elements Method
• Accessing the First Child Element with a Specified Name
• Using ReplaceAll to Change an Element's Subtree
• Accessing an Element's Child Elements Using the Elements Method
• Using the OfType Operator to Return Just the Elements
• Use LINQ to restrict the sequence of XML nodes to get comment only
• Adding a Node to the End of the Specified Node's Child Nodes with Add
• Adding a Node to the Beginning of the Specified Node's Child Nodes with AddFirst
• Adding a Node in the Specified Node's Child Nodes with AddBeforeSelf
• Adding a Node in a Specific Location of the Specified Node's Child Nodes with AddAfterSelf
• Deleting a Specific Node with Remove
• Deleting a Sequence of Nodes with Remove
• Removing a Node's Content with RemoveAll
• Updating a Node's Value
• Add annotations based on their type attribute
• Enumerate through the elements and retrieve the element's annotation:

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