All ports check the machine UDP, TCP listening, TCP client connections

  Private  BOOL ISPortUsed ( int Port) 
        { 
            the IList portUsed = PortUsing ();
             return portUsed.Contains (Port); 
        } 

        Private the IList PortUsing () 
        { 
            // Get information network connection and communication statistics local computer 
            IPGlobalProperties ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties (); 

            // return all the local computer Tcp listeners 
            the IPEndPoint [] = ipsTCP ipGlobalProperties.GetActiveTcpListeners (); 

            // return all the local computer UDP listener 
            the IPEndPoint [] = ipsUDP ipGlobalProperties.GetActiveUdpListeners (); 

            //Back Internet Protocol version on the local computer 4 (IPV4 Transmission Control Protocol (TCP) connection information. 
            TcpConnectionInformation [] = tcpConnInfoArray ipGlobalProperties.GetActiveTcpConnections (); 

            List < int > = Allports new new List < int > (); 
            allPorts.AddRange ( ipsTCP.Select (n- => n.Port)); 
            allPorts.AddRange (ipsUDP.Select (n- => n.Port)); 
            allPorts.AddRange (tcpConnInfoArray.Select (n- => n.LocalEndPoint.Port)); 

            return Allports; 
        }

 All source code Download: https://download.csdn.net/download/hanghangz/11250029