.net 在 C# 中，如何判断 TCP 端口是否可用

发布于02月21日

在C#中，要使用TcpClient或一般情况下连接到套接字，我如何首先判断机器上的某个端口是否空闲？

more info:个这是我使用的代码:

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

推荐答案

由于您使用的是TcpClient，这意味着您正在判断打开的TCP端口.System.Net.NetworkInformation名称空间中有很多好的对象.

使用IPGlobalProperties对象可以得到TcpConnectionInformation个对象的数组，然后可以查询端点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.