C# SQLHelper类

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以前做的很多项目都用到了SQLHelper类今天心血来潮就像把他贴出来了

public class SQLHelper
    {

        private SqlConnection conn = null;
        private SqlCommand cmd = null;
        private SqlDataReader sdr = null;
        /// <summary>
        /// 获取配置文件中的数据库地址
        /// </summary>
        public SQLHelper()
        {
            string connStr = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
            conn = new SqlConnection(connStr);
        }
        /// <summary>
        /// 数据库连接的打开
        /// </summary>
        /// <returns></returns>
        public SqlConnection Getconn()
        {
            if (conn.State == ConnectionState.Closed)//查看数据库状态并打开
            {
                conn.Open();
            }

            return conn;
        }

        /// <summary>
        /// 执行带不带参数的增删改SQL语句或者存储过程
        /// </summary>
        /// <param name="sql">增删改查SQL</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回受影响的行数</returns>
        public int ExecuteNonQuery(string sql,CommandType ct)
        {
            int res;

            using (cmd = new SqlCommand(sql, Getconn()))//定义其具有两个方法对数据库的连接及进行查询
            {
                cmd.CommandType = ct;//定义sql语句类型；

                res = cmd.ExecuteNonQuery();
            }

            return res;


        }

        /// <summary>
        /// 执行带参数的增删改SQL语句或者存储过程
        /// </summary>
        /// <param name="sql">增删改查SQL</param>
        /// <param name="paras">要查询的参数</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回受影响的行数</returns>
        public int ExecuteNonQuery(string sql, SqlParameter[] paras, CommandType ct)
        {
            int res;
            using (cmd = new SqlCommand(sql, Getconn()))//定义其具有两个方法对数据库的连接及进行查询
            {
                cmd.CommandType = ct;//定义sql语句类型；
                cmd.Parameters.AddRange(paras);
                res = cmd.ExecuteNonQuery();
            }
            return res;
        }

        /// <summary>
        /// 执行带不带参数的查询SQL语句或者存储过程
        /// </summary>
        /// <param name="sql">要查询的SQL</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回查询到到的data表</returns>
        public DataTable ExecuteQuery(string sql,CommandType ct)
        {


            DataTable dt = new DataTable();

            cmd = new SqlCommand(sql, 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语句或者存储过程
        /// </summary>
        /// <param name="sql">要查询的SQL</param>
        /// <param name="paras">要查询的参数</param>
        /// <param name="ct">命令类型</param>
        /// <returns>返回查询到到的data表</returns>
        public DataTable ExecuteQuery(string sql,SqlParameter[] paras,CommandType ct)
        {


            DataTable dt = new DataTable();
            cmd = new SqlCommand(sql, Getconn());
            cmd.CommandType = ct;
            cmd.Parameters.AddRange(paras);
            using (sdr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                dt.Load(sdr);
            }

            return dt;
        }
    }