如何使用C＃（socket通信）来检查TCP/IP端口可用性

Question

我已经创建了一个使用TCP/IP套接字文件传输communication.Now我想添加一个功能，检查TCP/IP coonection就具体的远程服务器的应用程序端口号（无论是否可用于转移）。所以，请有任何人帮助我。提前感谢。

如果（string.IsNullOrEmpty（txtIP.Text）） 回报;

如果（string.IsNullOrEmpty（ “8001”）） 回报;

   int port; 
       hostAddress = Dns.GetHostEntry(txtIP.Text).AddressList[0]; 
       int.TryParse("8001", out port); 
       StateObject state = new StateObject(); 
       if (hostAddress.AddressFamily == AddressFamily.InterNetwork) 
        state.workSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); 
       else if (hostAddress.AddressFamily == AddressFamily.InterNetworkV6) 
        state.workSocket = new Socket(AddressFamily.InterNetworkV6, SocketType.Stream, ProtocolType.Tcp); 

       SocketAsyncEventArgs telnetSocketAsyncEventArgs = new SocketAsyncEventArgs(); 
       telnetSocketAsyncEventArgs.RemoteEndPoint = new IPEndPoint(hostAddress, port); 
       telnetSocketAsyncEventArgs.Completed += new 
        EventHandler<SocketAsyncEventArgs>(telnetSocketAsyncEventArgs_Completed); 

       state.workSocket.ConnectAsync(telnetSocketAsyncEventArgs) 

私人无效telnetSocketAsyncEventArgs_Completed（对象发件人，的SocketAsyncEventArgs E） { 尝试 { 如果（e.SocketError == SocketError.Success） { 如果（e.LastOperation == SocketAsyncOperation.Connect） { MessageBox.Show（ “服务正在运行”，hostAddress.ToString（）， MessageBoxButtons.OK，MessageBoxIcon.Information）;

     ////send file if connection is established. 
        Socket clientSock = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); 
        byte[] fileName = Encoding.UTF8.GetBytes(m_fName); //file name 
        byte[] fileData = File.ReadAllBytes(txtFilePath.Text); //file 
        byte[] fileNameLen = BitConverter.GetBytes(fileName.Length); //lenght of file name 
        m_clientData = new byte[fileNameLen.Length + fileName.Length + fileData.Length]; 

        fileNameLen.CopyTo(m_clientData, 0); 
        fileName.CopyTo(m_clientData, fileNameLen.Length); 
        fileData.CopyTo(m_clientData, fileNameLen.Length + fileName.Length); 

        //Code for Progress bar 
        lblmsg.Text = ""; 
        double divider; 
        int extra; 
        fileProgress.Value = 0; 
        divider = (double)m_clientData.Length/1024; 
        divider = Math.Ceiling(divider); 
        fileProgress.Maximum = m_clientData.Length; 
        int packet = 0; 
        for (int i = 0; i < divider; i++) 
        { 
         if (i == (divider - 1)) 
         { 
          extra = (m_clientData.Length) - (i * 1024); 
          clientSock.Send(m_clientData, packet, extra, SocketFlags.None); 
         } 
         else 
         { 
          clientSock.Send(m_clientData, packet, 1024, SocketFlags.None); 
          packet = packet + 1024; 
          fileProgress.Value += 1024; 
         } 
        } 
        clientSock.Close(); 
        fileProgress.Value = fileProgress.Maximum; 
        lblSender.Text = "File upload is completed."; 
        clientSocket.Disconnect(true); 
        // } 

       } 
      } 
      else 
      { 
       bPortAvailble = false; 
       MessageBox.Show("Service Is not Running", e.SocketError.ToString(), 
        MessageBoxButtons.OK, MessageBoxIcon.Error); 
      } 
     } 
     catch (SocketException ex) 
     { 
      MessageBox.Show(ex.Message, "Service Is not Running", 
       MessageBoxButtons.OK, MessageBoxIcon.Error); 
     } 
    } 


} 

Answer 1

您可以尝试使用TcpClient建立连接，并捕获异常： TcpClient。

在你的情况，你正在使用Socket类的地方，看看这里： Socket class。如果你不Connect第一Send方法应该是失败的，从这里引用：

如果您使用的是无连接的协议，则必须调用此方法之前调用Connect，或发送会引发SocketException。

所以首先使用Connect，并捕捉它是否抛出SocketExcpetion。