Add new XElement to Xdocument

c#, nfc, windows-phone-8, xml

Solution

Try this:

public void saveTag()
{
    using (var storage = IsolatedStorageFile.GetUserStoreForApplication())
    {
        XDocument document;
        XElement tagRegistry = null;

        if (storage.FileExists("/tagRegistry.xml"))
        {
            using(var stream = storage.OpenFile("/tagRegistry.xml", FileMode.Open))
            {
                document = XDocument.Load(stream);
            }

            tagRegistry = document.Descendants("SmartSafe").FirstOrDefault();
        }
        else
        {
            document = new XDocument();
        }

        if(tagRegistry == null)
        {
            tagRegistry = new XElement("SmartSafe");
            document.Add(tagRegistry);
        }

        XElement newTag = new XElement("Tag",
            new XElement("tag", stringUid),
            new XElement("name", desiredName),
            new XElement("latitude", latitude),
            new XElement("longitude", longitude));

        tagRegistry.Add(newTag);

        using (Stream stream = storage.CreateFile("/tagRegistry.xml"))
        {
            document.Save(stream);
        }
    }
}

Problem

I have the following code, which successfully writes to an XML file. However, it overwrites each time because of the tagRegistry.Save() call being made. How can I add a new XElement to the existing file? At the moment the file is simply overwritten. ``` public void saveTag() { if (File.Exists("/tagRegistry.xml")) { XElement tagRegistry = XElement.Load("/tagRegistry.xml"); XElement newTag = new XElement("Tag", new XElement("tag", stringUid), new XElement("name", desiredName), new XElement("latitude", latitude), new XElement("longitude", longitude)); tagRegistry.Add(newTag); using (var storage = IsolatedStorageFile.GetUserStoreForApplication()) { using (Stream stream = storage.CreateFile("/tagRegistry.xml")) { tagRegistry.Save(stream); } } } else { XDocument tagRegistry = new XDocument(new XElement("SmartSafe")); tagRegistry.Element("SmartSafe").Add(new XElement("Tag", new XElement("tag", stringUid), new XElement("name", desiredName), new XElement("latitude", latitude), new XElement("longitude", longitude))); using (var storage = IsolatedStorageFile.GetUserStoreForApplication()) { using (Stream stream = storage.CreateFile("/tagRegistry.xml")) { tagRegistry.Save(stream); } } } } ```

Original source