如何检查状态并决定执行代码的哪一部分

Question

我有这个代码：

//open database connection on the server
                con = new MySqlConnection("server=localhost;database=GPS;uid=root;pwd=****");
                con.Open();
                if (con.State == ConnectionState.Closed)
                {
                    cmd = new MySqlCommand("insert into data values (null, ?Parname , ?Parname2, ?Parname3, ?Parname4, ?Parname5, ?Parname6, ?Parname7);", con);
                    cmd.Parameters.Add("?Parname", MySqlDbType.Double).Value = Math.Round(deciLat, 5);
                    cmd.Parameters.Add("?Parname2", MySqlDbType.Double).Value = Math.Round(deciLon, 5);
                    cmd.Parameters.Add("?Parname3", MySqlDbType.Timestamp).Value = DateTime.Now;
                    if (card_number != null)
                    {
                        cmd.Parameters.Add("?Parname4", MySqlDbType.VarChar).Value = card_number;
                    }
                    else
                    {
                        cmd.Parameters.Add("?Parname4", MySqlDbType.VarChar).Value = null;
                    }
                    cmd.Parameters.Add("?Parname5", MySqlDbType.VarChar).Value = ConfigSettings.ReadSetting("reg");
                    cmd.Parameters.Add("?Parname6", MySqlDbType.VarChar).Value = ConfigSettings.ReadSetting("ser");
                    cmd.Parameters.Add("?Parname7", MySqlDbType.Double).Value = ellipHeight;
                    cmd.ExecuteNonQuery();
                    lastDBUpdate = DateTime.Now;
                }
                else
                {
                    // local mysql database
                    con = new MySqlConnection("server=localhost;database=temp_GPS;uid=root;pwd=******");
                    con.Open();
                    if (con.State == ConnectionState.Open)
                    {
                        cmd = new MySqlCommand("insert into temp_data values (null, ?Parname , ?Parname2, ?Parname3, ?Parname4, ?Parname5, ?Parname6, ?Parname7);", con);
                        cmd.Parameters.Add("?Parname", MySqlDbType.Double).Value = Math.Round(deciLat, 5);
                        cmd.Parameters.Add("?Parname2", MySqlDbType.Double).Value = Math.Round(deciLon, 5);
                        cmd.Parameters.Add("?Parname3", MySqlDbType.Timestamp).Value = DateTime.Now;
                        if (card_number != null)
                        {
                            cmd.Parameters.Add("?Parname4", MySqlDbType.VarChar).Value = card_number;
                        }
                        else
                        {
                            cmd.Parameters.Add("?Parname4", MySqlDbType.VarChar).Value = null;
                        }
                        cmd.Parameters.Add("?Parname5", MySqlDbType.VarChar).Value = ConfigSettings.ReadSetting("reg");
                        cmd.Parameters.Add("?Parname6", MySqlDbType.VarChar).Value = ConfigSettings.ReadSetting("ser");
                        cmd.Parameters.Add("?Parname7", MySqlDbType.Double).Value = ellipHeight;
                        cmd.ExecuteNonQuery();
                        lastDBUpdate = DateTime.Now;
                    }
                }

如果连接状态正常并且与服务器建立连接然后将结果保存在服务器上，我想让我的代码正常工作，如果与服务器的连接失败，则连接并保存到我的本地数据库，这将始终可以访问。

有人可以安排我的代码按我的意愿工作吗，因为我不知道如何实现它。

谢谢

Answer 1

创建一个函数 GetConnection() 并使用此函数始终获取连接。

写下检查连接状态的代码并在此基础上返回连接。

public MySqlConnection GetConnection(MySqlConnection con)
{
        if (con.State == ConnectionState.Closed)
       {
           // local mysql database
             con = new MySqlConnection("server=localhost;database=temp_GPS;uid=root;pwd=******");
            con.Open();
       }

          return con;
    }