private static void ReadOrderData(string connectionString)
{
    string queryString =
        "SELECT OrderID, CustomerID FROM dbo.Orders;";

    using (SqlConnection connection =
               new SqlConnection(connectionString))
    {
        SqlCommand command =
            new SqlCommand(queryString, connection);
        connection.Open();

        SqlDataReader reader = command.ExecuteReader();

        // Call Read before accessing data.
        while (reader.Read())
        {
            Console.WriteLine(String.Format("{0}, {1}",
                reader[0], reader[1]));
        }

        // Call Close when done reading.
        reader.Close();
    }
}


SqlDataReader怎么用啊，reader[0], reader[1]怎么可以像 数组一样用呢
请老鸟指教，这reader[0] reader[1]是什么意思啊

0 和1  代表，你要读取的表的列名的索引号，也可以直接写成你要读取的列名[“某某”]