c# - 在 C# 中，如何检查 TCP 端口是否可用？

Question

在 C# 中使用 TcpClient 或通常连接到套接字，我如何首先检查我的机器上某个端口是否空闲？

更多信息: 这是我使用的代码:

TcpClient c;
//I want to check here if port is free.
c = new TcpClient(ip, port);

Answer 1

由于您使用的是 TcpClient，这意味着您正在检查打开的 TCP 端口。 System.Net.NetworkInformation 命名空间中有很多可用的好对象。

使用 IPGlobalProperties 对象获取一组 TcpConnectionInformation 对象，然后您可以查询端点 IP 和端口。

---

 int port = 456; //<--- This is your value
 bool isAvailable = true;

 // Evaluate current system tcp connections. This is the same information provided
 // by the netstat command line application, just in .Net strongly-typed object
 // form.  We will look through the list, and if our port we would like to use
 // in our TcpClient is occupied, we will set isAvailable to false.
 IPGlobalProperties ipGlobalProperties = IPGlobalProperties.GetIPGlobalProperties();
 TcpConnectionInformation[] tcpConnInfoArray = ipGlobalProperties.GetActiveTcpConnections();

 foreach (TcpConnectionInformation tcpi in tcpConnInfoArray)
 {
   if (tcpi.LocalEndPoint.Port==port)
   {
     isAvailable = false;
     break;
   }
 }

 // At this point, if isAvailable is true, we can proceed accordingly.