title: Failed to convert parameter value string to a IEnumerable
body: <p>I have a Dictionary. I am only trying to grab the keys and use them to update a database. </p>
  
  <pre><code>foreach (string key in dt.Keys)
  {
      var param = comm.Parameters.AddWithValue("@_AccountList", key);
      var paddingParam = comm.Parameters.AddWithValue("@padding", padding);
      var dateStartParam = comm.Parameters.AddWithValue("@proc_dateStart", startDate);
      var dateEndParam = comm.Parameters.AddWithValue("@proc_dateEnd", endDate);
      //table valued parameters
      param.SqlDbType = SqlDbType.Structured;
      var reader = comm.ExecuteNonQuery();
  }
  </code></pre>
  
  <p>The data type in my stored procedure is <code>varchar</code>, which should work. I'm not sure why it wants to convert my keys to IEnumerable. Could it have something to do with using Table valued Parameters?</p>