XML dynamic fields to LINQ

<PVdata>
  <dev>
      <pvname>bbharp1</pvname>
      <pvtype>harp</pvtype>
      <isactive>true</isactive>
      <beamline>J</beamline>
      <displaynamex>harp1x</displaynamex>
      <displaynamey>harp1y</displaynamey>
  </dev>
  <dev>
      <pvname>bbharp2</pvname>
      <pvtype>harp</pvtype>
      <isactive>true</isactive>
      <beamline>J</beamline>
      <displaynamex>harp2x</displaynamex>
      <displaynamey>harp2y</displaynamey>
  </dev>
  <dev>
      <pvname>bbharp22</pvname>
      <pvtype>harp</pvtype>
      <isactive>true</isactive>
      <beamline>X2</beamline>
      <displaynamex>harp22</displaynamex>
      <displaynamey>harp22</displaynamey>
 </dev>

</PVData>

Hi

I have the following code reading the above XML

  XmlReader Readxml = XmlReader.Create (fname, new XmlReaderSettings ());
  dsXML = new DataSet ();
  dsXML.ReadXml (Readxml);
  
  dtDevs = new DataTable ();
  dtDevs = dsXML.Tables["dev"];

   gridHarps.DataSource = dsXML.Tables["dev"];         // just to display data in grid

   //Close xml reader
   Readxml.Close ();

  var w = from r in dtDevs.AsEnumerable()

              select r;
 

  foreach (var b in w)
    {
        tBox.Text += b.pvname + Environment.NewLine;                // this fails as it wants b.fields<string>("pvname")
    }

>>

I can change the LINQ to:

 var w = from r in dtDevs.AsEnumerable()

              select new 

              {

                pvname = r.fields<string>("pvname")

                pvtype = r.fields<string>("pvtype")

               }

However, the XML file can be configured with new "fields", so I cannot use the above.

Thanks

Amien