SqlDataReader控制多个数据集

using System;
using System.Data;
using System.Data.SqlClient;

namespace Chapter12
{
    class MultipleResults
    {
        static void Main(string[] args)
        {
            // connection string
            string connString = @"
                            server = .;
                            integrated security = true;
                            database = northwind
                         ";

            // query 1
            string sql1 = @"
                        select
                           companyname,
                           contactname
                        from
                           customers
                        where
                           companyname like 'A%'
                     ";

            // query 2
            string sql2 = @"
                        select
                           firstname,
                           lastname
                        from
                           employees
                     ";

            // combine queries
            string sql = sql1 + sql2;

            SqlDataReader rdr = null;
           
            SqlConnection conn = null;

            try
            {
                 // create connection
                conn = new SqlConnection(connString);
                // open connection
                conn.Open();

                // create command
                SqlCommand cmd = new SqlCommand(sql, conn);

                // 执行两个sql分句后返回两个数据集
                rdr = cmd.ExecuteReader();

                // loop through result sets
                do{
                    while (rdr.Read())
                    {
                        // Print one row at a time
                        Console.WriteLine("{0} : {1}", rdr[0], rdr[1]);
                    }
                    Console.WriteLine("".PadLeft(60, '='));
                }
                while (rdr.NextResult()); //SqlDataReader.NextResult()函数前进至下一个数据集。

               
            }
            catch (Exception e)
            {
                Console.WriteLine("Error Occurred: " + e);
            }
            finally
            {
                // close data reader
                rdr.Close();
                // Close connection
                conn.Close();
            }
        }
    }
}

//所有代码来自书籍《Begining C# Databases From Novice to Professional》