制作ado开发辅助工具类SqlHelper

 public static class SqlHelper
    {
        //通过配置文件获取连接字符创
        private static readonly string constr = ConfigurationManager.ConnectionStrings["str"].ConnectionString;
        /// <summary>
        /// 执行增,删,改的方法
        /// </summary>
        /// <param name="sql">要执行的sql语句</param>
        /// <param name="spt">参数化查询的参数</param>
        /// <returns>影响的行数</returns>
        public static int ExecuteNonquery(string sql, params SqlParameter[] spt)
        {
            using (SqlConnection con = new SqlConnection(constr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    con.Open();
                    if (spt != null)
                    {
                        cmd.Parameters.AddRange(spt);
                    }
                    return cmd.ExecuteNonQuery();
                }
            }
        }
        /// <summary>
        /// 执行返回一行一列数据的方法
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="spt"></param>
        /// <returns></returns>
        public static object ExecuteScalar(string sql, params SqlParameter[] spt)
        {
            using (SqlConnection con = new SqlConnection(constr))
            {
                using (SqlCommand cmd = new SqlCommand(sql, con))
                {
                    con.Open();
                    if (spt != null)
                    {
                        cmd.Parameters.AddRange(spt);
                    }
                    return cmd.ExecuteScalar();
                }
            }
        }
        /// <summary>
        /// 执行查询语句的方法
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="spt"></param>
        /// <returns>SqlDataReader类型</returns>
        public static SqlDataReader ExecuteReader(string sql, params SqlParameter[] spt)
        {
            SqlConnection con = new SqlConnection(constr);
            using (SqlCommand cmd = new SqlCommand(sql, con))
            {
                if (spt != null)
                {
                    cmd.Parameters.AddRange(spt);
                }

                try
                {
                    con.Open();
                    return cmd.ExecuteReader(CommandBehavior.CloseConnection);
                }
                catch (Exception)
                {
                    con.Close();
                    con.Dispose();
                    throw;
                }
            }
        }
        /// <summary>
        /// 用到DataAdapter的方法,
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="spt"></param>
        /// <returns>DataTable类型</returns>
        public static DataTable ExecuteAdapter(string sql, params SqlParameter[] spt)
        {
            DataTable ds = new DataTable();
            using (SqlDataAdapter da = new SqlDataAdapter(sql, constr))
            {
                if (spt != null)
                {
                    da.SelectCommand.Parameters.AddRange(spt);
                }
                da.Fill(ds);
            }
            return ds;

        }
    }