Edit Specific Element in Xdocument

Edit specific Element in XDocument

With using System.Xml.Linq; it becomes

 var doc = XElement.Load(fileName);
 var saveGame = doc
      .Element("savegames")
      .Elements("savegame")
      .Where(e => e.Element("IdNumber").Value == "2")
      .Single();

 saveGame.Element("balance").Value = "50";

 doc.Save(fileName);

Update Specific value of specific XML tag using XDocument

Use XDocument to parse the xml string. Find the money XElement and update his value.

public void Button1_Click(object sender, EventArgs e)
{
    XDocument doc = XDocument.Load(@"XMLFile1.xml");

    var result = doc.Root.Descendants("money").FirstOrDefault();

    if (result == null)
       return;

    result.Value = txt.Text;
    doc.Save(@"XMLFile1.xml"); 

}

EDIT

Check dotNetFiddle

How to update all instances of an element in XDocument?

Linq is a query language, so you can't directly use it to modify the value, but you can easily select all the Resource elements in the document with it and iterate/change them.

For example:

// or load from xml, however you have it
var xDoc = XDocument.Load(@"c:\temp\myxml.xml"); 
// iterate every Resource element
foreach (XElement element in xDoc.Descendants("Resource"))            
    element.Value = "Hello, world";

That will pick out every Resource element in the XML regardless of where it is in the hierarchy, which in your case, is what you need. If you needed to target it more specifically, you could either use an XPath expression or further Linq calls such as Element() which work on a single level of the hierarchy.

Edit existing element in XDocument

Method DescendantsAndSelf(XName name) returns every element that has matching name and all descendant elements of this element (MSDN). In your case that's body element with its children.

You probably want to form your XML like the following one:

<?xml version="1.0" encoding="UTF-8"?>
<body>
   <someElement>
      <id>1</id>
      <disc>B</disc>
      <type>Mark</type>
      <value>5</value>
   </someElement>
   <someElement>
      <id>2</id>
      <disc>A</disc>
      <type>Mark</type>
      <value>10</value>
   </someElement>
</body>

so you can get single someElement XML node like this:

var target = doc.DescendantsAndSelf("someElement")
              .Where(e => e.Element("disc").Value == Disc
                  && e.Element("type").Value.ToString().Equals(Type.ToString())
                  && e.Element("value").Value.ToString().Equals(OldMark.ToString()))
              .Single();

Debug.WriteLine(target.ToString());

Get Element from XDocument & Edit Attribute

You can try this way :

XNamespace ns = "http://fake.com/services";
XElement xmlPromotionElement = xmlPromotionResponse.Descendants(ns+"Promotion")
                                                   .SingleOrDefault();
xmlPromotionElement.Attribute("PromotionId").Value = "XXX";

Use simple XNamespace + local-name to reference an element in namespace. Then you can use .Attribute() method to get XAttribute from an XElement and change the attribute's value.

How to modify a specific XElement into a file.xml

So for updating all Banana's Color to YELLOW use this code:

        string xmlFilePath = @"C:\Users\codroipomad\Desktop\slave\Test.xml";
        XDocument xdoc = XDocument.Load(xmlFilePath);
        XNamespace ns = "http://www.fruitauthority.fake";

        var elBanana = xdoc.Descendants()?.Elements(ns + "FruitName")?.Where(x => x.Value == "Banana")?.Ancestors(ns + "Fruit");

        foreach (var item in elBanana)
        {
            var elColor = item.Elements(ns + "FruitColor").FirstOrDefault();

            //check se il file esiste,se non esiste lo crea
            if (!File.Exists(xmlFilePath))
                File.Create(xmlFilePath).Dispose();

            if (elColor != null)
            {
                elColor.Value = "YELLOW";
            }

        }

        xdoc.Save(xmlFilePath);

How to change the value of an element in an xml file?

Use LINQ and XDocument:

string applicationName = "Test";
XDocument xdocument = XDocument.Load("Data.xml");
var appName = xdocument.Elements("applicationName").Single();
appName.Value = applicationName;
xdocument.Save("Data.xml");

But you should add System.Xml.Linq to your using directives first.

Edit Specific Element in Xdocument