[C#] 在类里实例化自身的应用实例<上位机通信>

  public sealed class HoldingRegisters : ModbusTypeAbstract<ushort[]>
  {
        public static HoldingRegisters Instance { get; } = new HoldingRegisters();

    //static HoldingRegisters(){}
    private HoldingRegisters(){}

        public override ushort[] Read(request req)
    {
      return GetOrAddConnection(req.connectiontype, req.destination)?.ReadHoldingRegisters(req.slaveid, req.address, req.count);
    }

    public override void Write(writerequest<ushort[]> wreq)
    {
      GetOrAddConnection(wreq.connectiontype,wreq.destination)?.WriteMultipleRegisters(wreq.slaveid, wreq.address, wreq.data);
    }

  }

  public abstract class ModbusTypeAbstract<T> : IModbusType<T>
  {
    ConcurrentDictionary<string, IModbusMaster> connections = new ConcurrentDictionary<string, IModbusMaster>();

    public abstract T Read(request req);
    public abstract void Write(writerequest<T> wreq);

        public virtual void ConnCount()
        {
            foreach (var conn in connections)
            {
                Console.WriteLine($"{ conn.Key } {conn.Value}");
            }
        }
    /// <summary>
    /// 验证IP连接字符串
    /// </summary>
    /// <param name="conn">IP连接字符串</param>
    /// <param name="ip"></param>
    /// <param name="port"></param>
    /// <returns></returns>
    private bool verifyIPConnectionString(string conn, out IPAddress ip, out int port)
    {
      port = 0;
      ip = null;
      var connectionarray = conn.Split(':');
      if (connectionarray.Length != 2)
      {
        return false;
      }

      if (!int.TryParse(connectionarray[1], out port))
      {
        return false;
      }
      if (!IPAddress.TryParse(connectionarray[0], out ip))
      {
        return false;
      }
      return true;
    }
    protected IModbusMaster GetOrAddConnection(ConnectionType ctype, string conn)
    {
            switch (ctype)
       {
        case ConnectionType.SERIALRTU:
          return connections.GetOrAdd(conn, (arg) =>
            {
                            return ModbusSerialMaster.CreateRtu(new SerialPort(conn));
            });
        case ConnectionType.SERIALASCII:
          return connections.GetOrAdd(conn, (arg) =>
            {
                return ModbusSerialMaster.CreateAscii(new SerialPort(conn));
            });
        case ConnectionType.TCP:
          int port; IPAddress ip;
          if (!verifyIPConnectionString(conn, out ip, out port))
          {
            return null;
          }

          return connections.GetOrAdd(conn, (arg) =>
          {
            return ModbusIpMaster.CreateIp(new TcpClient(ip.ToString(), port));
          });
      }
      return null;

    }
  }
}