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 

这使我在第二个代码块（在while循环中调用的代码块）中出现错误，表示已经存在与该连接关联的datareader。 我怎么能让它工作，因为我确信有办法。

 using(reader) { System.Data.DataTable dt = new System.Data.DataTable(); dt.Load(reader); foreach(DataRow row in dt.Rows) { addtolog("mysql",row["nations_name"].ToString()); int nation_ID = int.Parse(row["nations_ID"].ToString()); string nation_name = row["nations_name"].ToString(); string user_ID = row["nations_user"].ToString(); addnation(nation_ID, nation_name, user_ID); } }