title: Unable to cast object of type 'System.Int16' to type 'System.String' - AsEnumerable().ToDictionary
body: <pre><code>Dictionary&lt;string, DataRow&gt; dtUsers;
  using (DataSet dsmyTable = DbConnection.db_Select_Query
                       ("use myDb select * from myTable"))
  {
      dtUsers= dsmyTable .Tables[0].AsEnumerable().
           ToDictionary(row =&gt; row.Field&lt;string&gt;("UserId"));
  }
  </code></pre>
  
  <p>Alright UserId is a <code>smallint</code> column
  But I want to cast it as string.</p>
  
  <p>How should I modify the above linq ?</p>