title: Merge datatables but ignore duplicated rows
body: <p>I have the following code, its a custom people picker for sharepoint 2010.</p>
  
  <p>It searches by username, but also by the person name.
  Because its a contains search, if I try with part of my username: <code>cia</code></p>
  
  <p>It shows my duplicated rows because that matches the username but also the person name.</p>
  
  <p>this is my code (I cant use LINQ:</p>
  
  <pre><code> protected override int IssueQuery(string search, string groupName, int pageIndex, int pageSize)
   {
      try
      {
          // Find any user that has a matching name
          var table = ADHelper.ExecuteNameQuery(RootPath, search);
  
          // 20249: Search by username, method was already done, but it was not being called.
          var table2 = ADHelper.ExecutesAMAccountNameQuery(search);
          table2.Merge(table,);
          PickerDialog.Results = table2;
  </code></pre>