SQLHelper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 SQLhepler    {        private SqlConnection connection = null;        private SqlCommand comm = null;        private SqlDataReader der = null;        public SQLhepler()        {            string connstr = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString;            connection = new SqlConnection(connstr);        }        private SqlConnection getconn()        {            if (connection.State == ConnectionState.Closed)            {                connection.Open();            }            return connection;        }        /// <summary>        /// 执行不带参数的sql增删改语句或存储过程        /// </summary>        /// <param name="cmdtext">增删改sql或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdtext, CommandType ct)        {            int ints;            try            {                comm = new SqlCommand(cmdtext, getconn());                comm.CommandType = ct;                ints = comm.ExecuteNonQuery();            }            catch (Exception ex)            {                throw ex;            }            finally            {                if (connection.State == ConnectionState.Open)                {                    connection.Close();                }            }            return ints;        }        /// <summary>        /// 执行不带参数的sql查询语言或存储过程        /// </summary>        /// <param name="cmdtext">sql查询语言或存储过程</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdtext, CommandType ct)        {            DataTable dt = new DataTable();            comm = new SqlCommand(cmdtext, getconn());            comm.CommandType = ct;            using (der = comm.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(der);            }            return dt;        }        /// <summary>        /// 执行带参数的sql增删改语句或存储过程        /// </summary>        /// <param name="cmdtext">sql增删改语句或存储过程</param>        /// <param name="para">参数集合</param>        /// <param name="ct">命令类型</param>        /// <returns></returns>        public int ExecuteNonQuery(string cmdtext, SqlParameter[] para, CommandType ct)        {            int ints;            using (comm = new SqlCommand(cmdtext, getconn()))            {                comm.CommandType = ct;                comm.Parameters.AddRange(para);                ints = comm.ExecuteNonQuery();            }

            return ints;        }        /// <summary>        /// 执行带参数的sql查询语句或存储过程;        /// </summary>        /// <param name="cmdtext"></param>        /// <param name="para"></param>        /// <param name="ct"></param>        /// <returns></returns>        public DataTable ExecuteQuery(string cmdtext, SqlParameter[] para, CommandType ct)        {            DataTable dt = new DataTable();            comm = new SqlCommand(cmdtext, getconn());            comm.CommandType = ct;            comm.Parameters.AddRange(para);            using (der = comm.ExecuteReader(CommandBehavior.CloseConnection))            {                dt.Load(der);            }            return dt;        }    }}