c#MySQL第二个DataReader在DataReader while循环中

正如你可能从标题中猜到的那样,我试图这样做：

    #region check new nations
    private void checknewnations()
    {
        addtolog("server","Checking for new nations");
        string sql = "SELECT * FROM " + variables.tbl_nations + " WHERE nations_new=0";
        MySqlCommand cmd = new MySqlCommand(sql, connection);
        MySqlDataReader reader = cmd.ExecuteReader();

        while (reader.Read())
        {
            addtolog("mysql",reader["nations_name"].ToString());

            int nation_ID = int.Parse(reader["nations_ID"].ToString());
            string nation_name = reader["nations_name"].ToString();
            string user_ID = reader["nations_user"].ToString();


            addnation(nation_ID, nation_name, user_ID);
        }
        addtolog("server","Finished checking for new nations.");
        //connection.Close();
        reader.Dispose();
    }
    #endregion

在while循环中调用它：

    #region addnation
    private void addnation(int nationIDnot, string nationName, string userID)
    {
        string nationID = makesixdigits(nationIDnot);
        string userName = "";

        string sql = "SELECT * FROM " + variables.tbl_users + " WHERE users_ID=" + userID;
        MySqlCommand cmd = new MySqlCommand(sql, connection);
        MySqlDataReader reader = cmd.ExecuteReader();


        while (reader.Read())
        {
            userName = reader["users_name"].ToString();
        }
        reader.Dispose();
        addtolog("add", "[" + nationID.ToString() + "] " + nationName + " [" + userID + "] " + userName);
    }
    #endregion

这给了我第二个代码块(在while循环中调用的代码块)中的错误,表示已经存在与该连接相关联的datareader.我怎么能让它工作,因为我相信有办法.

解决方法:

在2008连接字符串中,您可以通过MultipleActiveResultSets = true获得多个活动结果集;我没有使用mySQL所以我不确定,但也许你使用的是ADO提供商.

否则,只需建立另一个连接 – 不要重复使用同一个连接.

标签：datareader,mysql,connection,database,c-2
来源： https://codeday.me/bug/20190901/1786534.html