AccessHelper 需修改

using System;

using System.Collections.Generic;

using System.Configuration;

using System.Data;

using System.Data.OleDb;

using System.Data.SqlClient;

using System.Linq;

using System.Web;

namespace CyObject.BLL

{

    public class DataAccessDAL

    {

        protected static OleDbConnection conn = new OleDbConnection();

        protected static OleDbCommand comm = new OleDbCommand();

        public DataAccessDAL()

        {

            //init

        }

        /// <summary>

        /// 打开数据库

        /// </summary>

        private static void openConnection()

        {

            if (conn.State == ConnectionState.Closed)

            {

                conn.ConnectionString = @"Provider=Microsoft.Jet.OleDb.4.0;Data Source=" +System.Web.HttpContext.Current.Server.MapPath(ConfigurationManager.AppSettings["myconn"]);//web.config文件里设定。

                comm.Connection = conn;

                try

                {

                    conn.Open();

                }

                catch (Exception e)

                { throw new Exception(e.Message); }

            }

        }

        /// <summary>

        /// 关闭数据库

        /// </summary>

        private static void closeConnection()

        {

            if (conn.State == ConnectionState.Open)

            {

                conn.Close();

                conn.Dispose();

                comm.Dispose();

            }

        }

        public static object ExecuteScalar(string sql, params OleDbParameter[] parameters) {

            openConnection();

            comm.CommandText = sql;

            comm.Parameters.AddRange(parameters);

            return comm.ExecuteScalar();

        }

        public static int ExecuteNonQuery(string sql, params OleDbParameter[] parameters) {

            openConnection();

            comm.CommandText = sql;

            comm.Parameters.AddRange(parameters);

            return comm.ExecuteNonQuery();

        }

        public static DataTable ExecuteDataTable(string sql, params OleDbParameter[] parameters) {

            openConnection();

            comm.CommandText = sql;

            comm.Parameters.AddRange(parameters);

            DataSet dataset = new DataSet();

            OleDbDataAdapter apdater = new OleDbDataAdapter(comm);

            apdater.Fill(dataset);

            return dataset.Tables[0];

        }

    }

}