title: How to join datatable using LINQ
body: <p>I have two DataTables:</p>
  
  <p>dt1 - personid, name</p>
  
  <p>dt2 - personid</p>
  
  <p>I want to create a third datatable to include records from dt1 when they are NOT in dt2 using LINQ.  In this case, I can bind the third datatable to a dropdownlist.</p>
  
  <p>any help would be great! thanks!</p>