Pulling string from xml

Question

The xml is coming from a url and all I need is the pull the string "N0014E1" from it. I am not sure why this code is not working. I put a try block around it and I get a "Data root level is invalid"

xml:

<obj is="c2g:Network " xsi:schemaLocation="http://obix.org/ns/schema/1.0/obi/xsd" href="http://192.168.2.230/obix/config/">
  <ref name="N0014E1" is="c2g:LOCAL c2g:Node"xsi:schemaLocation="http://obix.org/ns/sc/1.0/obix/xsd" href="N0014E1/"></ref>
</obj>

C# code:

    public static string NodePath = "http://" + MainClass.IpAddress + ObixPath;


    public static void XMLData()
    {
        XmlDocument NodeValue = new XmlDocument();
        NodeValue.LoadXml(NodePath);


        var nodes = NodeValue.SelectNodes(NodePath);

        foreach (XmlNode Node in nodes)
        {
            HttpContext.Current.Response.Write(Node.SelectSingleNode("//ref name").Value);
            Console.WriteLine(Node.Value);
        }

        //Console.WriteLine(Node);
        Console.ReadLine();
    }

Answer 1

Your SelectNodes and SelectSingleNode commands are incorrect. Both expect an xpath string to identify the node.

Try the following

string xml = @"<obj is=""c2g:Network "" href=""http://192.168.2.230/obix/config/""><ref name=""N0014E1"" is=""c2g:LOCAL c2g:Node"" href=""N0014E1/""></ref></obj>";

XmlDocument NodeValue = new XmlDocument();
NodeValue.LoadXml(xml);
XmlNode r = NodeValue.SelectSingleNode("//ref[@name]");
if (r != null)
{
    System.Diagnostics.Debug.WriteLine(r.Attributes["name"].Value);
}

Also, Note, that LoadXml method simply loads an xml string; it will not load from a remote url.

As @kevintdiy has pointed out your xml is not entirely correct. In the sample above I have stripped out the xsi reference as you are lacking a definition for it.

If you have access to the source xml, either remove the reference to xsi if its not required or add a definition for it to the root node.

If this is not possible, then you may want to consider using regular expression or other string based methods for getting the value.