using System;

using System.Collections.Generic;

using System.Configuration;

using System.Data;

using System.Data.OleDb;

using System.Linq;

using System.Web;

namespace vr

{

    public class ConnDbForAcccess

    {

          /// <summary>

        /// 连接数据库字符串

        /// </summary>

        private string connectionString;

        /// <summary>

        /// 存储数据库连接（保护类，只有由它派生的类才能访问）

        /// </summary>

        protected OleDbConnection Connection;

        /// <summary>

        /// 构造函数：数据库的默认连接

        /// </summary>

        public ConnDbForAcccess()

        {

            string connStr;

            connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString.ToString();

           // connStr = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"].ToString(); //从web.config配置中读取

            connectionString = connStr;

            //connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + HttpContext.Current.Request.PhysicalApplicationPath + connStr;

           // connectionString = System.Configuration.ConfigurationSettings.AppSettings["ConnectionString"].ToString();

            //

            Connection = new OleDbConnection(connectionString);

        }

        /// <summary>

        /// 构造函数：带有参数的数据库连接

        /// </summary>

        /// <param name="newConnectionString"></param>

        public ConnDbForAcccess(string newConnectionString)

        {

            //connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + HttpContext.Current.Request.PhysicalApplicationPath + newConnectionString;

            connectionString = newConnectionString;

            Connection = new OleDbConnection(connectionString);

        }

        /// <summary>

        /// 获得连接字符串

        /// </summary>

        public string ConnectionString

        {

            get

            {

                return connectionString;

            }

        }

        /// <summary>

        /// 执行SQL语句没有返回结果，如：执行删除、更新、插入等操作

        /// </summary>

        /// <param name="strSQL"></param>

        /// <returns>操作成功标志</returns>

        public bool ExeSQL(string strSQL)

        {

            bool resultState = false;

            Connection.Open();

            OleDbTransaction myTrans = Connection.BeginTransaction();

            OleDbCommand command = new OleDbCommand(strSQL, Connection, myTrans);

            try

            {

                command.ExecuteNonQuery();

                myTrans.Commit();

                resultState = true;

            }

            catch

            {

                myTrans.Rollback();

                resultState = false;

            }

            finally

            {

                Connection.Close();

            }

            return resultState;

        }

        /// <summary>

        /// 执行SQL语句返回结果到DataReader中

        /// </summary>

        /// <param name="strSQL"></param>

        /// <returns>dataReader</returns>

        private OleDbDataReader ReturnDataReader(string strSQL)

        {

            Connection.Open();

            OleDbCommand command = new OleDbCommand(strSQL, Connection);

            OleDbDataReader dataReader = command.ExecuteReader();

            Connection.Close();

            return dataReader;

        }

        /// <summary>

        /// 执行SQL语句返回结果到DataSet中

        /// </summary>

        /// <param name="strSQL"></param>

        /// <returns>DataSet</returns>

        public DataSet ReturnDataSet(string strSQL)

        {

            Connection.Open();

            DataSet dataSet = new DataSet();

            OleDbDataAdapter OleDbDA = new OleDbDataAdapter(strSQL, Connection);

            OleDbDA.Fill(dataSet, "objDataSet");

            Connection.Close();

            return dataSet;

        }

        /// <summary>

        /// 执行一查询语句，同时返回查询结果数目

        /// </summary>

        /// <param name="strSQL"></param>

        /// <returns>sqlResultCount</returns>

        public int ReturnSqlResultCount(string strSQL)

        {

            int sqlResultCount = 0;

            try

            {

                Connection.Open();

                OleDbCommand command = new OleDbCommand(strSQL, Connection);

                OleDbDataReader dataReader = command.ExecuteReader();

                while (dataReader.Read())

                {

                    sqlResultCount++;

                }

                dataReader.Close();

            }

            catch

            {

                sqlResultCount = 0;

            }

            finally

            {

                Connection.Close();

            }

            return sqlResultCount;

        }

    }

}