Question

I want to update the xml document and i need to return the updated xml in string. I am trying like below. when i save the document it expects the file name. but i dont want to save this as file. i just want to get the updated xml in string.

        string OldXml = @"<Root>
                                  <Childs>
                                    <first>this is first</first>
                                    <second>this is second </second>
                                  </Childs        
                                  </Root>";

        XmlDocument NewXml = new XmlDocument();
        NewXml.LoadXml(OldXml );

        XmlNode root = NewXml.DocumentElement;
        XmlNodeList allnodes = root.SelectNodes("*");

        foreach (XmlNode eachnode in allnodes)
        {
            if (eachnode.Name == "first")
            {
                eachnode.InnerText = "1";
            }
        }

        NewXml.Save();
        string newxml = NewXml.OuterXml;

Answer 1

You don’t need to call Save method because string is immutable, your problem is in root.SelectNodes("*"), it just get child nodes, not all level of nodes. You need to go one more level:

  foreach (XmlNode eachnode in allnodes)
        {
            var firstNode = eachnode.ChildNodes.Cast<XmlNode>()
                              .SingleOrDefault(node => node.Name == "first");
            if (firstNode != null)
            {
                firstNode.InnerText = "1";
            }
        }


  string newxml = NewXml.OuterXml;

It would be strongly recommended using LINQ to XML, it’s simpler:

var xDoc = XDocument.Parse(OldXml);
foreach (var element in xDoc.Descendants("first"))
    element.SetValue(1);

string newXml = xDoc.ToString();