Question

Let’s say I have a file like this:

<outer>
  <inner>
    <nodex attr="value1">text</attr>
    <nodex attr="value2">text</attr>
  </inner>
</outer>

Basically what I want to do is, in C# (constrained to .net 2.0 here), this (pseudocode):

foreach node
    if(node eq 'nodex')
        update attr to newvalue

When complete, the xml file (on disk) should look like:

<outer>
  <inner>
    <nodex attr="newvalue1">text</attr>
    <nodex attr="newvalue2">text</attr>
  </inner>
</outer>

These two look marginally promising:

Overwrite a xml file value

Setting attributes in an XML document

But it’s unclear whether or not they actually answer my question.

---

I’ve written this code in the meantime:

Here’s a more minimal case which works:

    public static void UpdateXML()
    {
        XmlDocument doc = new XmlDocument();
        using (XmlReader reader = XmlReader.Create("XMLFile1.xml"))
        {
            doc.Load(reader);
            XmlNodeList list = doc.GetElementsByTagName("nodex");
            foreach (XmlNode node in list)
            {
                node.Attributes["attr"].Value = "newvalue";
            }
        }
        using (XmlWriter writer = XmlWriter.Create("XMLFile1.xml"))
        {
            doc.Save(writer);
        }
    }

Answer 1

Here is a sample script that can be run from LinqPad

var x = @"<outer>
  <inner>
    <nodex attr=""value1"">text</nodex>
    <nodex attr=""value2"">text</nodex>
  </inner>
</outer>";

XmlDocument doc = new XmlDocument();
doc.LoadXml(x);

foreach (XmlNode n in doc.SelectNodes("//nodex"))
{
    n.Attributes["attr"].Value = "new" + n.Attributes["attr"].Value.ToString();
}

doc.OuterXml.Dump();