List open Sockets in .NET

[jman]

Is there a way to determine if a particular socket is open on the localhost?

I'm looking for something that will either return a list of open sockets or a function that will take a port number and return some sort of status value, boolean or otherwise.

I am trying to write an app that will determine if another application I wrote has started correctly and is listening for incoming requests.

Thanks

[vijaydiwakar]

Is there a way to determine if a particular socket is open on the localhost?

I'm looking for something that will either return a list of open sockets or a function that will take a port number and return some sort of status value, boolean or otherwise.

I am trying to write an app that will determine if another application I wrote has started correctly and is listening for incoming requests.

Thanks

u may try this

 
Sub GetSerialPortNames()
    ' Show all available COM ports.
    For Each sp As String In My.Computer.Ports.SerialPortNames
        ListBox1.Items.Add(sp)
    Next
End Sub
 
 
 

[jman]

u may try this

 
Sub GetSerialPortNames()
    ' Show all available COM ports.
    For Each sp As String In My.Computer.Ports.SerialPortNames
        ListBox1.Items.Add(sp)
    Next
End Sub
 
 
 

Thanks for the response, but I should have been more specific:
1. I am talking about a tcp socket port, not a serial port.
2. I would prefer a C#-ish way of doing this.

[radcaesar]

//Creates the Socket for sending data over TCP.
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Stream,
ProtocolType.Tcp );

// Connects to host using IPEndPoint.
s.Connect(EPhost);
if (!s.Connected)
{
strRetPage = "Unable to connect to host";
}
// Use the SelectWrite enumeration to obtain Socket status.
if(s.Poll(-1, SelectMode.SelectWrite)){
Console.WriteLine("This Socket is writable.");
}
else if (s.Poll(-1, SelectMode.SelectRead)){
Console.WriteLine("This should not print. Because this is not a listening Socket," +
" no incoming connecton requests are expected. " );
}
else if (s.Poll(-1, SelectMode.SelectError)){
Console.WriteLine("This Socket has an error.");
}

[jman]

Thanks radcaesar.

I had tried a similiar approach using TcpClient but that caused the program listening to the socket to wait for an incoming message. This solution does not.

Thanks

[jman]

Thanks radcaesar.

I had tried a similiar approach using TcpClient but that caused the program listening to the socket to wait for an incoming message. This solution does not.

Thanks

It seems I was mistaken. This still causes the listening program to expect data to be sent. The problem is that under certain circumstances the program will freeze waiting for the data to be transmitted.