[转载]SqlConnection,SqlCommand,SqldataReader的用法总结:

http://www.cnblogs.com/winner/archive/2008/01/09/1032651.html

using System;
using System.Data;
using System.Configuration;
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;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//-------------------SqlConnection,SqlCommand,SqldataReader的用法-------------------//

//下面的4种形式等价,如果你的数据库是Windows连接方法,直接把连接字符串改成"server=.;database=northwind;integrated security=true;"
//如果你的数据库是某个实例名,直接把"server=."改成"server=你的计算机名实例名"就可以了

SqlConnection con = new SqlConnection();
con.ConnectionString = "server=.;database=northwind;uid=sa;pwd=;"; //双引号中的最后一个分号可以去掉
con.Open();
SqlCommand cmd = con.CreateCommand();
cmd.CommandText = "select * from customers";
SqlDataReader sdr = cmd.ExecuteReader();
this.GridView1.DataSource = sdr;
this.GridView1.DataBind();
sdr.Close();
con.Close();

//SqlConnection con = new SqlConnection();
//con.ConnectionString = "server=.;database=northwind;uid=sa;pwd=;"; //双引号中的最后一个分号可以去掉
//con.Open();
//SqlCommand cmd = new SqlCommand("select * from customers");
//cmd.Connection = con;
//SqlDataReader sdr = cmd.ExecuteReader();
//this.GridView1.DataSource = sdr;
//this.GridView1.DataBind();
//sdr.Close();
//con.Close();

////我最经常用这一种,同时连接对象是整个程序的公共对象,所以我一般会把数据库连接封装到一个类中,这样就可以在程序的任何地方随时调用
//SqlConnection con = new SqlConnection("server=.;database=northwind;uid=sa;pwd=;"); //双引号中的最后一个分号可以去掉
//con.Open();
//SqlCommand cmd = new SqlCommand("select * from customers", con);
//SqlDataReader sdr = cmd.ExecuteReader();
//this.GridView1.DataSource = sdr;
//this.GridView1.DataBind();
//sdr.Close();
//con.Close();

//SqlConnection con = new SqlConnection();
//con.ConnectionString = "server=.;database=northwind;uid=sa;pwd=;"; //双引号中的最后一个分号可以去掉
//con.Open();
//SqlCommand cmd = new SqlCommand();
//cmd.Connection = con;
//cmd.CommandText = "select * from customers";
//cmd.CommandType = CommandType.Text; //这条语句是多余的,因为默认就是Text
//SqlDataReader sdr = cmd.ExecuteReader();
//this.GridView1.DataSource = sdr;
//this.GridView1.DataBind();
//sdr.Close();
//con.Close();
}