concat two columns in combobox from database

I am trying to concat two columns but something is going wrong.... my output is not displayed .

String Query = " SELECT pa_forename , pa_surname FROM [ICPS].[dbo].[parking_attendants] order by pa_forename ";
 SqlConnection conDataBase = new SqlConnection(conString);
 SqlCommand cmdDataBase = new SqlCommand(Query, conDataBase);
 SqlDataReader myReader;
  try
{
  conDataBase.Open();
  myReader = cmdDataBase.ExecuteReader();
 while (myReader.Read())
                {
string pa_forename = myReader["pa_forename " +"," + "pa_surname"].ToString();
 comboBox1.Items.Add(pa_forename);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);

            }