资讯发布系统中的SQLHelper助手类

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data;using System.Data.SqlClient;using System.Configuration;namespace DAL{    public class SQLHelper    {        private SqlConnection conn = null;        private SqlCommand cmd = null;        private SqlDataReader sdr = null;        public SQLHelper()        {            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;            conn = new SqlConnection(connStr);        }        private SqlConnection GetConn()        {            if (conn.State == ConnectionState.Closed)            {                conn.Open();            }            return conn;        }        /// <summary>        ///  执行不带参数的增删改SQL语句或存储过程        /// </summary>        /// <param name="cmdText">增删改SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdText, CommandType ct)        {            int res;            try            {                cmd = new SqlCommand(cmdText, GetConn());                cmd.CommandType = ct;                res = cmd.ExecuteNonQuery();            }            catch (Exception ex)            {                throw ex;            }            finally            {                if (conn.State == ConnectionState.Open)                {                    conn.Close();                }            }            return res;        }        /// <summary>        ///  执行带参数的增删改SQL语句或存储过程        /// </summary>        /// <param name="cmdText">增删改SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdText, SqlParameter[] paras, CommandType ct)        {            int res;            using (cmd = new SqlCommand(cmdText, GetConn()))            {                cmd.CommandType = ct;                cmd.Parameters.AddRange(paras);                res = cmd.ExecuteNonQuery();            }            return res;        }        /// <summary>        ///  执行查询SQL语句或存储过程        /// </summary>        /// <param name="cmdText">查询SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdText, CommandType ct)        {            DataTable dt = new DataTable();            cmd = new SqlCommand(cmdText, GetConn());            cmd.CommandType = ct;            using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(sdr);            }            return dt;        }        /// <summary>        ///  执行带参数的查询SQL语句或存储过程        /// </summary>        /// <param name="cmdText">查询SQL语句或存储过程</param>        /// <param name="paras">参数集合</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdText, SqlParameter[] paras, CommandType ct)        {            DataTable dt = new DataTable();            cmd = new SqlCommand(cmdText, GetConn());            cmd.CommandType = ct;            cmd.Parameters.AddRange(paras);            using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(sdr);            }            return dt;        }    }}

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Data;using System.Data.SqlClient;using System.Configuration;namespace DAL{    public class SQLHelper    {        private SqlConnection conn = null;        private SqlCommand cmd = null;        private SqlDataReader sdr = null;        public SQLHelper()        {            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;            conn = new SqlConnection(connStr);        }        private SqlConnection GetConn()        {            if (conn.State == ConnectionState.Closed)            {                conn.Open();            }            return conn;        }        /// <summary>        ///  执行不带参数的增删改SQL语句或存储过程        /// </summary>        /// <param name="cmdText">增删改SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdText, CommandType ct)        {            int res;            try            {                cmd = new SqlCommand(cmdText, GetConn());                cmd.CommandType = ct;                res = cmd.ExecuteNonQuery();            }            catch (Exception ex)            {                throw ex;            }            finally            {                if (conn.State == ConnectionState.Open)                {                    conn.Close();                }            }            return res;        }        /// <summary>        ///  执行带参数的增删改SQL语句或存储过程        /// </summary>        /// <param name="cmdText">增删改SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdText, SqlParameter[] paras, CommandType ct)        {            int res;            using (cmd = new SqlCommand(cmdText, GetConn()))            {                cmd.CommandType = ct;                cmd.Parameters.AddRange(paras);                res = cmd.ExecuteNonQuery();            }            return res;        }        /// <summary>        ///  执行查询SQL语句或存储过程        /// </summary>        /// <param name="cmdText">查询SQL语句或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdText, CommandType ct)        {            DataTable dt = new DataTable();            cmd = new SqlCommand(cmdText, GetConn());            cmd.CommandType = ct;            using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(sdr);            }            return dt;        }        /// <summary>        ///  执行带参数的查询SQL语句或存储过程        /// </summary>        /// <param name="cmdText">查询SQL语句或存储过程</param>        /// <param name="paras">参数集合</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdText, SqlParameter[] paras, CommandType ct)        {            DataTable dt = new DataTable();            cmd = new SqlCommand(cmdText, GetConn());            cmd.CommandType = ct;            cmd.Parameters.AddRange(paras);            using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(sdr);            }            return dt;        }    }}

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webconfig配置	<connectionStrings>		<add name="connStr" connectionString="server=niunan\sqlexpress; database=newssystem; uid=sa; pwd=123456"/>	</connectionStrings>

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