asp.net平台上连接数据库

 今天纠结了一上午的问题，于下午3点12分尘埃落定！
事情是这样的：
作为一个里程碑记录下吧，也算是我第一次将asp.net与数据库结合，并完成从软件编程到web的过渡。
在此感谢今天为我解决问题的“杀手”（也称老道），还有以前为我解决问题的大队、御风、华哥等牛...
言归正传，本文介绍一下怎样在asp.net平台上连接数据库：（C#编写的软件连接数据库见前几篇）
 using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Data.OleDb;
using System.Data.SqlClient;
using System.Runtime.InteropServices;
using System.Configuration;
using System.Web.UI.WebControls;
using System.Web.Services.Description;
public partial class _Default : System.Web.UI.Page
{
static DataSet ds;
int index;
protected void Page_Load(object sender, EventArgs e)
{
//set mode of textbox2 as password
//在asp.net中设置textbox 属性为password (C#中是passwordchar = ……)
TextBox2.TextMode = TextBoxMode.Password ;
//count the num of user,as we can add the new user with index++(as id)
string strConnection = ConfigurationManager.AppSettings["Str.Properties.Settings.masterConnectionString"].ToString();
SqlConnection objConnection = new SqlConnection(strConnection);
objConnection.Open();
string sql = "count user num";
sql="select userid as userid,name as name from judging";
SqlDataAdapter adp = new SqlDataAdapter(sql, objConnection);
ds = new DataSet();
ds.Clear();
adp.Fill(ds, "judging");
index = ds.Tables[0].Rows.Count+1;
}

//Register function
protected void Button1_Click(object sender, EventArgs e)
{
/******************method 1*******************/
//string strConnection = "Data Source=ZRQ-PC;";
//strConnection += "Initial Catalog=master;Integrated Security=True";
//SqlConne