using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Text;

 using System.Threading.Tasks;

 using System.Data;

 using System.Data.SqlClient;

 namespace ConsoleApplication2

 {

     class Program

     {

         //返回DataReader的函数

         static SqlDataReader returnDR()

         {

             string strConn = @"server=Joe-PC;database=AdventureWorks_WroxSSRS2012;uid=sa;pwd=root";

             SqlConnection conn = new SqlConnection(strConn);

             string strCmd = "SELECT ProductCategoryID,Name FROM Production.ProductCategory";

             SqlCommand cmd = new SqlCommand(strCmd, conn);

             conn.Open();

             SqlDataReader dr = cmd.ExecuteReader();

             return dr;

         }

         //Main中进行调用

         static void Main(string[] args)

         {

             SqlDataReader dr = returnDR();

             while (dr.Read())

             {

                 Console.WriteLine("{0}:{1}", dr["ProductCategoryID"], dr["Name"]);

             }

             dr.Close();

             //ExecuteReader函数提供了一种重载形式

             //允许通过参数指定DataReader与Connection对象的关联行为CommandBehavior.CloseConnection：

             //一旦关闭DataReader对象，则与该对象关联的Connection对象也自动关闭

         }

     }

 }