Question

asp.net的ExecuteReader()方法的用法

using System;using System.Collections;using System.Configuration;using System.Data;using System.Linq;using System.Web;using System.Web.Security;using System.Web.UI;using System.Web.UI.HtmlControls;using System.Web.UI.WebControls;using System.Web.UI.WebControls.WebParts;using System.Xml.Linq;using System.Data.SqlClient;namespace exam{    public partial class test : System.Web.UI.Page    {        protected void Page_Load(object sender, EventArgs e)        {            SqlCommand cmd = DB.createSqlcommand("select * from denglu where id=1");            SqlDataReader sdr = cmd.ExecuteReader();            //string a = sdr.GetName(0);            string a = Convert.ToString(sdr.GetValue(0));我想取出改行的id，但报错了            this.Label1.Text = a;        }    }} 上面这段代码有错，请问错在哪里？该怎样用ExecuteReader()从数据库中取出特定字段的值

Answer 1

ExecuteReader()这只是一个方法啊，SqlCommand cmd = DB.createSqlcommand("select * from denglu where id=1"); 你觉得这错没？

Answer 2

SqlConnection呢？

SqlCommand cmd = new SqlCommand(sql, con);
SqlDataReader da = cmd.ExecuteReader();