title: not able to use CopyToDataTable in linq for returning dataset
body: <p>how to return a <code>dataset</code> from <code>linq</code> in .net 3.5?</p>
  
  <p>I have seen in some sites that <strong>CopyToDataTable</strong> method is used but I am not able to use that methos as I cannot find System.data.datatableextensions reference in the ref list.
  Please help me out.</p>
  
  <p>Thanks  and regards,
  veena</p>