Append node to XML file?

You could use something like:

            XmlDocument doc = new XmlDocument();
            doc.Load("C:\\test.xml");

            XmlNode user = doc.CreateElement("user");
            user.AppendChild(doc.CreateElement("name")).InnerText = "xxx";
            user.AppendChild(doc.CreateElement("id")).InnerText = "1";

            XmlNode mark = doc.CreateElement("mark");
            mark.Attributes.SetNamedItem(doc.CreateAttribute("A")).InnerText = "10";
            mark.Attributes.SetNamedItem(doc.CreateAttribute("B")).InnerText = "20";

            user.AppendChild(mark);
            doc.FirstChild.AppendChild(user);

            doc.Save("C:\\test2.xml");

Whay I got the following error:
System.InvalidOperationException: The current node cannot contain other nodes
Source Error:
Line 126:     doc.FirstChild.AppendChild(user)

 

What does the XML you are appending to look like in full ? Is there a Schema or DTD associated with it ?

No schema no DTD

What does your full XML look like ?

Here is the full file:

<?xml version="1.0" encoding="utf-8"?>
<users>
     <user>
         <name> yyy</name>
          <id>1</id>
          <mark A="11" B="12" />
     </user>
     <user>
           <name> zzz</name>
           <id>2</id>
           <mark A="34" B="50" />
     </user>
</users>

Try it with just the snippet you posted before and see if that works.

Same error.

Many thanks