Mapping SqlDataReader results to classes
public static Listing Get(SqlConnection connection,int listingId)
    {
        Listing listing = null;
        SqlDataReader reader = null;
        try
        {
            SqlCommand cmd = Global.GetSQLCommand("[Listing].[GetDetails]", connection);
            Global.AddIntParameter(cmd, "@pListingId", listingId);

            reader = cmd.ExecuteReader();

            var colDictionary = Global.GetColumnsInReader(reader);

            while (reader.Read())
            {
                listing = new Listing(reader,colDictionary);
            }
        }
        catch (Exception e)
        {
            Global.HandleException(e);
        }
        finally
        {
            Global.DestroyReader(reader);
        }
        return listing;
    }

SqlCommand cmd = Global.GetSQLCommand("[Listing].[GetDetails]", connection);
Global.AddIntParameter(cmd, "@pListingId", listingId);
reader = cmd.ExecuteReader();

public static Dictionary<String,Int32> GetColumnsInReader(SqlDataReader reader)
{
     Dictionary<String, Int32> columns = new Dictionary<String, Int32>();
     for (int i = 0; i < reader.FieldCount; i++)
     {
        String columnName = reader.GetName(i);
        int columnIndex = reader.GetOrdinal(columnName);
        columns.Add(columnName, columnIndex);
     }

     return columns;
}

var colDictionary = Global.GetColumnsInReader(reader);

while (reader.Read())
{
    listing = new Listing(reader,colDictionary);
}

public Listing(SqlDataReader reader, Dictionary<String, Int32> colDictionary)
    : base(reader, colDictionary, "ListingId")
{
    _comment = Global.GetStringData(reader,colDictionary, "Comment");
    _description = Global.GetStringData(reader,colDictionary,"Description");
    _detailViewCount = Global.GetIntData(reader, colDictionary, "DetailViewCount");
    _vehicle = new Vehicle(reader, colDictionary);
}

public static String GetStringData(SqlDataReader reader, Dictionary<String, Int32>
                                    colDictionary, String columnName)
 {
    int columnIndex = 0;

    if (colDictionary.TryGetValue(columnName, out columnIndex))
    {
        if (reader.IsDBNull(columnIndex))
            return "";

        var test = reader.GetValue(columnIndex);
        return Convert.ToString(test);
    }

     return null;
   }