Question

我有以下代码，我基本上从SQL服务器中获取mysql和plonking的数据。

SQL Server部分工作正常，但我无法弄清楚如何保持mysql连接打开以进行更新。当它在foreach循环中执行mysql执行读取器时，它会出现错误：

An unhandled exception of type 'System.InvalidOperationException' occurred in MySql.Data.dll

Additional information: Connection must be valid and open.

代码：

 DB db = new DB();
            String sConfig_hostname = 
            String sConfig_dbname = 
            String sConfig_dbusername = 
            String sConfig_dbpassword = 
            string MyConString = "SERVER=" + sConfig_hostname + ";" +
                "DATABASE=" + sConfig_dbname + ";" +
                "UID=" + sConfig_dbusername + ";" +
                "PASSWORD=" + sConfig_dbpassword + ";Allow Zero Datetime=true;";
            MySqlConnection connection = new MySqlConnection(MyConString);
             string sQuery="Select * from inbox where Transferred = 0";

             MySqlDataAdapter myDA = new MySqlDataAdapter(sQuery, connection);
             MySqlCommandBuilder cmb=new MySqlCommandBuilder(myDA);

             DataTable MyDT = new DataTable();
             myDA.Fill(MyDT);

             foreach (DataRow row in MyDT.Rows)
             {
                String SQL = String.Format("Insert into Inbox (Message, Received, Sender) VALUES ('{0}', '{1}', '{2}')", GeneralFunctions.SQLescape(row["TextDecoded"].ToString()), row["ReceivingDateTime"].ToString(), row["SenderNumber"].ToString());
                String mySQL = "Update inbox set Transferred = 1 where ID = " + row["ID"].ToString();
                db.Update(SQL);

                MySqlCommand SQLup = new MySqlCommand(mySQL);
                MySqlDataReader reader = SQLup.ExecuteReader();

             }

Answer 1

MySqlConnection connection = new MySqlConnection(MyConString);
connection.open(); // insert this line

了解更多information

Answer 2

它失败的原因是因为你不想在这里执行一个阅读器，你只想执行语句和，因为你没有初始化带连接的命令：

MySqlConnection connection = new MySqlConnection(MyConString);
connection.Open();

...

MySqlCommand SQLup = new MySqlCommand(mySQL, connection);
SQLup.ExecuteNonQuery();

mySQL通过c＃将数据写入数据库

2 个答案: