mysql連接中的異常c＃

Question

我在connection.Open（）到遠程Mysql基地時遇到奇怪的異常。 此代碼工作正常，但有時會彈出此錯誤

這是一個代碼：

private static string
            DatabaseServer = "",
            DatabasePort = "",
            DatabaseName = "",
            DatabaseUserID = "",
            DatabasePassword = "";

    public static string ConnectionString = String.Format("SERVER={0};PORT={1};DATABASE={2};UID={3};PASSWORD={4}",

                DatabaseServer, DatabasePort, DatabaseName, DatabaseUserID, DatabasePassword);

                using (MySqlConnection connection = new MySqlConnection(ConnectionString))
                {
                    try
                    {
                        if (connection != null)
                        {
                            connection.Open();

                            string query = @"....";

                            MySqlCommand cmd = new MySqlCommand(query, connection);
                            cmd.CommandType = CommandType.Text;

                            using (MySqlDataReader dataReader = cmd.ExecuteReader())
                            {
                                while (dataReader.Read())
                                {

                                }
                            }        
                        }
                    }
                    catch
                    {}
                }

問題是什么時候連接.Open（）; 即使它在try {} catch {}它終止應用程序。

異常日志：

System.Reflection.TargetInvocationException: An exception occurred during the operation, making the result invalid. Check InnerException for exception details. InnerException. ---> MySql.Data.MySqlClient.MySqlException: Unable to connect to any of the specified MySQL hosts. ---> System.Exception: Call to GetHostEntry failed after 00:00:00 while querying for hostname '': SocketErrorCode=TryAgain, ErrorCode=11002, NativeErrorCode=11002. ---> System.Net.Sockets.SocketException: This is usually a temporary error during hostname resolution and means that the local server did not receive a response from an authoritative server.

   в System.Net.Dns.GetAddrInfo(String name)
   в System.Net.Dns.InternalGetHostByName(String hostName, Boolean includeIPv6)
   в System.Net.Dns.GetHostEntry(String hostNameOrAddress)
   в MySql.Data.Common.StreamCreator.GetDnsHostEntry(String hostname)
   ---  ---
   в MySql.Data.Common.StreamCreator.GetDnsHostEntry(String hostname)
   в MySql.Data.Common.StreamCreator.GetHostEntry(String hostname)
   в MySql.Data.Common.StreamCreator.GetStreamFromHost(String pipeName, String hostName, UInt32 timeout)
   в MySql.Data.Common.StreamCreator.GetStream(UInt32 timeout)
   в MySql.Data.MySqlClient.NativeDriver.Open()
   ---  ---
   в MySql.Data.MySqlClient.NativeDriver.Open()
   в MySql.Data.MySqlClient.Driver.Open()
   в MySql.Data.MySqlClient.Driver.Create(MySqlConnectionStringBuilder settings)
   в MySql.Data.MySqlClient.MySqlPool.GetPooledConnection()
   в MySql.Data.MySqlClient.MySqlPool.TryToGetDriver()
   в MySql.Data.MySqlClient.MySqlPool.GetConnection()
   в MySql.Data.MySqlClient.MySqlConnection.Open()
   в System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   в System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)
   ---  ---
   в System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary()
   в System.ComponentModel.RunWorkerCompletedEventArgs.get_Result()
   в Server.Engines.DonateSQL.bw_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e) в System.ComponentModel.BackgroundWorker.OnRunWorkerCompleted(RunWorkerCompletedEventArgs e)
   в System.ComponentModel.BackgroundWorker.AsyncOperationCompleted(Object arg)
   в System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   в System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   в System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   в System.Threading.ThreadPoolWorkQueue.Dispatch()
   в System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

我不知道該怎么做。 嘗試了一切，因為發生了什么而無法找到。

Answer 1

System.Exception：在查詢主機名''時，在00:00:00之后調用GetHostEntry失敗

看看你的調用代碼，看看為什么Databaseserver是一個空字符串的原因。 如果沒有發生這種情況，請將您的網絡男孩喚醒，因為看起來您的DNS出現了打嗝。 不知道你的設置是什么，但如果你能負擔得起用IP替換名字並且它停止發生，那么你可以用一個大臟手指指着它們。

Answer 2

可能存在網絡和/或DNS問題：

System.Reflection.TargetInvocationException：操作期間發生異常，導致結果無效。 檢查InnerException以獲取異常詳細信息。 的InnerException。 ---> MySql.Data.MySqlClient.MySqlException： 無法連接到任何指定的MySQL主機。 ---> System.Exception：在查詢主機名''時，在00:00:00之后調用GetHostEntry失敗：SocketErrorCode = TryAgain，ErrorCode = 11002，NativeErrorCode = 11002。 ---> System.Net.Sockets.SocketException： 這通常是主機名解析期間的臨時錯誤，意味着本地服務器沒有收到來自權威服務器的響應。