Create and Update an XML file in C#

In this article, i'll show you how to create and update an XML file in C#. Hope this help!

Create an XML file

Let's start by creating a new XML file. To do this, we'll use XmlTextWriter. Open your Main function and copy the code below:

static void Main(string[] args) {
    // create a new file
    string path = "E:\\Example.xml";
    XmlTextWriter writer = new XmlTextWriter(path, System.Text.Encoding.UTF8);

    // set output's view format
    writer.Formatting = Formatting.Indented;

    // write XML declaration
    writer.WriteStartDocument(true);

    // compose XML content
    writer.WriteStartElement("inventory");
        writer.WriteAttributeString("category", "vehicle");
        writer.WriteStartElement("item");
            writer.WriteAttributeString("id","p1");
            writer.WriteString("Car");
        writer.WriteEndElement();
        writer.WriteStartElement("item");
            writer.WriteAttributeString("id", "p2");
            writer.WriteString("Bicycle");
        writer.WriteEndElement();
    writer.WriteEndElement();

    // close session
    writer.Close();
}

Result
Example.xml

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<inventory category="vehicle">
    <item id="p1">Car</item>
    <item id="p2">Bicycle</item>
</inventory>

Update an XML file

Now that we have created a simple XML file using XmlTextWriter. Next, let's modify it by XDocument. See the code below:

static void Main(string[] args){
    string path = "E:\\Example.xml";
    try {
        XDocument doc = XDocument.Load(path);
        XElement res = doc.Element("inventory");
        // remove last item
        res.LastNode.Remove();
        // new item
        XElement item = new XElement("item", "Motobike");
        XAttribute att = new XAttribute("id", "p3");
        item.Add(att);
        // add to inventory
        res.Add(item);
        // save file
        doc.Save(path);
    }
    catch (Exception e){
        throw e; // file not found
    }
}

Result
Example.xml

<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<inventory category="vehicle">
    <item id="p1">Car</item>
    <item id="p3">Motobike</item>
</inventory>