数据库连接助手类

/*
 * 创建人：李要南
 * 创建时间：2008-12-5 18:53
 * 说明：数据库助手类
 * 版权所有：李要南
 */
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>
        ///  该方法执行传入的sql增删改语句
        /// </summary>
        /// <param name="sql">要执行的sql增删改语句</param>
        /// <returns>返回更新的记录数</returns>
        public int ExecuteNonQuery(string cmdText, CommandType ct)
        {
            int res = 0;
            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>
        /// 该方法执行带参数的sql增删改语句
        /// </summary>
        /// <param name="sql">要执行的sql增删改语句</param>
        /// <param name="paras">参数集合</param>
        /// <returns></returns>
        public int ExecuteNonQuery(string cmdText, SqlParameter[] paras, CommandType ct)
        {
            int res = 0;
            using (cmd = new SqlCommand(cmdText, GetConn()))
            {
                cmd.Parameters.AddRange(paras);
                cmd.CommandType = ct;
                res = cmd.ExecuteNonQuery();
            }
            return res;
        }

       /// <summary>
       /// 该方法执行传入的sql查询语句或存储过程
       /// </summary>
        /// <param name="cmdText">sql查询语句或存储过程</param>
       /// <param name="ct"></param>
       /// <returns></returns>
        public DataTable ExecuteReader(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>
        /// 该方法执行带参数的sql查询语句                     
        /// </summary>
        /// <param name="cmdText">要执行的sql查询语句</param>
        /// <param name="paras">参数集合</param>
        /// <returns></returns>
        public DataTable ExecuteReader(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;
        }

      
    }

}