C＃Winforms Npgsql 3.0.5“操作已在进行中”尝试在同一连接中运行多个命令时出现错误 [英] C# Winforms Npgsql 3.0.5 "An operation already in progress" error when trying to run multiple commands inside same connection

问题描述

我试图在C＃Winforms中运行以下代码段。这段代码与pgsql 2.2.6适配器正常工作。可以做什么校正，以便与pgsql3.0.5适配器正常工作？感谢。

I'm trying to run the following snippet in C# Winforms. This piece of code is working well with pgsql 2.2.6 adapter. What correction can be made in order to work fine with pgsql3.0.5 adapter? Thanks.

NpgsqlConnection conn = new NpgsqlConnection(MainForm2.MyConString);
        {
            conn.Open();
            using (NpgsqlCommand cmd = new NpgsqlCommand("SELECT rfid,name,sc_id from passenger ORDER by name", conn))
            {
                NpgsqlDataReader dr = cmd.ExecuteReader();
                while (dr.Read())
                {
                    var obj = new PassengerClass
                    {
                        RFID = dr.GetString(0),
                        Name = dr.GetString(1),
                        sc_id = dr.GetInt32(2)
                    };
                    s = dr.GetString(0);
                    try { ret.Add(s, obj); }
                    catch (Exception ex) { SM.Debug("Fail to add RFID Name in hash RFID:" + s + ex.ToString()); }
                }
            }
            MainForm2.PassHash = ret;
            try
            {
                using (NpgsqlCommand cmd = new NpgsqlCommand(string.Format("UPDATE place set useridx ={0} where useridx=0", MainForm2.userIDX), conn))
                    cmd.ExecuteNonQuery();

                using (NpgsqlCommand cmd = new NpgsqlCommand(string.Format("UPDATE zonename set useridx ={0} where useridx=0", MainForm2.userIDX), conn))
                    cmd.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                SM.Debug("Error on update users IDX for place and zone with value 0 :" + ex.ToString());
            }

因此，在第二个命令语句中，它给出以下错误： p>

So, at the second command statement it gives me the following error:

在Npgsql.dll中发生类型为System.InvalidOperationException的第一次机会异常

A first chance exception of type 'System.InvalidOperationException' occurred in Npgsql.dll

其他信息：操作已在进行中。

Additional information: An operation is already in progress.

编辑附加信息：

EDIT Additional info:

你需要处理在第一个ExecuteReader调用中获得的NpgsqlDataReader，用一个使用语句包装它就像你对NpgsqlCommand一样。

You need to dispose of the NpgsqlDataReader which you get in the first ExecuteReader call, wrap it with a using statement just like you do with your NpgsqlCommand.

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