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》