阅读器关闭时尝试调用 Read 无效

[bleach001]

页面载入时候分别从两张表里读取数据，调试过程中，能查出第一张的数据，查询第二张表的是后出错了 ：阅读器关闭时尝试调用 Read 无效

 string sql = "SELECT  top 1 accountName, money, date FROM  Account WHERE accountName =" + "'" + name + "'" + " ORDER BY date DESC";

            using (SqlDataReader reader = DBHelper.ExecuteReader(sql))
            {
                if (reader.Read())  //这里报错

两张表都用了using 。

[子夜__]

用这种

/// <summary>
        /// 执行有参的查询 返回DataTable
        /// </summary>
        /// <returns>返回DataTable</returns>
        public static DataTable ReturnDataTable(string cmdtext)
        {
            SqlConnection cn = new SqlConnection();
            cn.ConnectionString = "数据库连接字符串";
            DataTable dt = new DataTable();
            SqlCommand cmd = new SqlCommand();
            cmd = new SqlCommand(cmdtext, cn);
            cmd.CommandType = CommandType.Text; ;
            SqlDataReader dr = null;
            using (dr = cmd.ExecuteReader(CommandBehavior.CloseConnection))
            {
                dt.Load(dr);
            }
            return dt;
        }

[bleach001]

最后改了试了很久，就是把第一条查询注释了还是报错，最后我改了下语句

    string sql = "SELECT  top 1 balance  FROM  Account WHERE accountName =" + "'" + name + "'" + " ORDER BY date DESC";  
   SqlDataReader reader = DBHelper.ExecuteReader(sql)//原语句 报错
 if（reader.Read()）
   ```
    string sql = "SELECT  top 1 balance  FROM  Account WHERE accountName =@name ORDER BY date DESC"; 
   SqlDataReader reader = DBHelper.ExecuteReader(sql,new SqlParameter("@name",name))//这样写就好了 

很郁闷的问题