C#Winform使用SqlConnection，内部连接致命错误。错误状态：18。请问是什么错误，如何排除？

Question

如题。代码中贴出的内容在本地服务器完全正常运行，在网络服务器从未正常发送。
基于给出的信息，服务器在sqlYOG中可以正常打开。

string connString = "server = tcp:(这里是一段正确的sql服务器ip地址), (这里是正确的sql服务器端口号); uid = " + textBox2.Text + "; pwd =" + textBox4.Text + "; database = 正确的数据库名称";
string judg, create, updt, inpu=总之这些都是正确的指令;
SqlConnection conn = new SqlConnection(connString);
conn.Open();
SqlCommand comm = new SqlCommand();
comm.Connection = conn;
comm.CommandText = judg + create;
comm.ExecuteNonQuery();
comm.CommandText = updt;
comm.ExecuteNonQuery();
comm.CommandText = inpu;
comm.ExecuteNonQuery();
conn.Close();

MessageBox弹出的字段是"Failed! "+Exception ex.Message。

Server management:

内部连接致命错误。错误状态: 18 (System.Data)

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程序位置:

在 System.Data.SqlClient.TdsParserStateObject.TryProcessHeader()
在 System.Data.SqlClient.TdsParser.ConsumePreLoginHandshake(SqlAuthenticationMethod authType, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean& marsCapable, Boolean& fedAuthRequired)
在 System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, Boolean withFailover, Boolean isFirstTransparentAttempt, SqlAuthenticationMethod authType, Boolean disableTnir, SqlAuthenticationProviderManager sqlAuthProviderManager)
在 System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean ignoreSniOpenTimeout, TimeoutTimer timeout, Boolean withFailover, Boolean isFirstTransparentAttempt, Boolean disableTnir)
在 System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(ServerInfo serverInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString connectionOptions, SqlCredential credential, TimeoutTimer timeout)
在 System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(TimeoutTimer timeout, SqlConnectionString connectionOptions, SqlCredential credential, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance)
在 System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTransientFaultHandling, SqlAuthenticationProviderManager sqlAuthProviderManager)
在 System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
在 System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup, DbConnectionOptions userOptions)
在 System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
在 System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions)
在 System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions)
在 System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry)
在 System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
在 System.Data.SqlClient.SqlConnection.Open()
在 Microsoft.SqlServer.Management.SqlStudio.Explorer.ObjectExplorerService.ValidateConnection(UIConnectionInfo ci, IServerType server)
在 Microsoft.SqlServer.Management.UI.ConnectionDlg.Connector.ConnectionThreadUser()

Answer 1

你是不是连mysql数据库，SqlConnection只用于sqlserver数据库
要连接mysql数据库，要用到MySql.Data或MySqlConnector，这两个可以通过NuGet安装

https://www.cnblogs.com/guxin/p/csharp-connect-mysql-database.html