安卓初学者

using System;
using System.Data;
using System.Configuration;
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;
using System.Text.RegularExpressions;
using System.Collections;
using System.Collections.Generic;
namespace SecurityService
{
    public class DBOperation : IDisposable
    {
        public static SqlConnection sqlCon;  //用于连接数据库  

        //将下面的引号之间的内容换成上面记录下的属性中的连接字符串  
        private String ConServerStr = @"Data Source=ARRON-PC;Initial Catalog=Security;Integrated Security=True";

        //默认构造函数  
        public DBOperation()
        {
            if (sqlCon == null)
            {
                sqlCon = new SqlConnection();
                sqlCon.ConnectionString = ConServerStr;
                sqlCon.Open();
            }
        }

        //关闭/销毁函数，相当于Close()  
        public void Dispose()
        {
            if (sqlCon != null)
            {
                sqlCon.Close();
                sqlCon = null;
            }
        }

        /// <summary>  
        /// 获取所有货物的信息  
        /// </summary>  
        /// <returns>所有货物信息</returns>  
        public List<string> ShowInfo()
        {
            List<string> list = new List<string>();

            try
            {
                string sql = "select * from Find";
                SqlCommand cmd = new SqlCommand(sql, sqlCon);
                SqlDataReader reader = cmd.ExecuteReader();

                while (reader.Read())
                {
                    //将结果集信息添加到返回向量中  
                    list.Add(reader[0].ToString());
                    list.Add(reader[1].ToString());
                    list.Add(reader[2].ToString());

                }

                reader.Close();
                cmd.Dispose();

            }
            catch (Exception)
            {

            }
            return list;
        }