新手问问题散分SqlDataReader rs = new Executereader();

Question

为什么提示缺少using指令
  到底却了什么呢？

Answer 1

using System.Data.SqlClient;...
SqlDataReader rs = new Executereader();

Answer 2

(ExecuteReader不是对象,是个方法,所以不能new)这样做的:
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();

Answer 3

using System.Data.SqlClient;或者写全
System.Data.SqlClient.SqlDataReader

Answer 4

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient; 有了啊

Answer 5

Executereader 是什么? 是你自己的类吗?如果是要写名称空间.