CODEWITHSUNDEEP
c#socketstcplistener
user3138965
user3138965

Reputation: 129

Only one usage of each socket address is normally permitted

Suppose I used TcpListener to start listen any IP address and port, it works for the first time. But soon after I restart the program, I got this error 'Only one usage of each socket address is normally permitted'. It sounds like I didn't close tcpListener when I exit my program, I did that in Form_closing but didn't works. Later I found a way to solve this problem by changing my port each time, although this could fix problem I need a fix port. Here how my codes look like.

TcpListener tcpListener;
Socket socketClient;
const int PORT_LISTEN_SERVER = 7568;

tcpListener = new TcpListener(IPAddress.Any, PORT_LISTEN_SERVER);
tcpListener.Start();                        //Error at this line
socketClient = tcpListener.AcceptSocket();
IPEndPoint ipend = (IPEndPoint)socketClient.RemoteEndPoint;
toolStripLabel1.Text = "Connection from " + IPAddress.Parse(ipend.Address.ToString());

How I close my listener connection

try
{
 MessageBox.Show("Try to clean up!");
 tcpListener.Stop();
 socketClient.Close();
}
catch { MessageBox.Show("Error CleanUp!"); }

Updated: Suppose I changed into function make recursion. To check perhaps tcpListener's stop method could solve this problem. Every time I try to run the function, I'm keep getting Error Message. It seems like stop method could not solve this.

private void BeginListen()
{           
 try
 {
  tcpListener = new TcpListener(IPAddress.Any, PORT_LISTEN_SERVER);
  tcpListener.Start();
  MessageBox.Show("tcpListener is started");
 }
 catch (Exception ex)
 { 
  MessageBox.Show("Error at: " + ex);
  tcpListener.Stop();
  BeginListen();
}

Only one usage of each socket address is normally permitted

Upvotes: 1

Views: 4536

Answers (1)

Armali
Armali

Reputation: 19395

Well,I just solved it myself. Socket.Close is executed before it assign to. – user3138965

Upvotes: 0

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