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Hi all, I programmed a network program that uses UDP protocol. The program simply send text to other program and the other program received and respond with answer.
The problem is I have multiple forms the two forms uses the same port and for that my Visual Studio give an exception that I can't use same protocol/network/ or session.
So, after I finish working with the first form close it at this event the port must closed and the second form works with the same port that opened in the first form.

' this object is thread that receives data.
    Dim t As New Threading.Thread(AddressOf ReceiveMessage)
' this function will start the listenning
    Public Function Listen(ByVal port As Integer) As Boolean
        _LPort = port
        _IsListening = True
        _Timer.Interval = 100
        _IPEP = New IPEndPoint(IPAddress.Any, _LPort)
        _UDPlsn = New UdpClient(_IPEP)
        done = False
    End Function
' this function will stop listenning
    Public Sub StopListen()
        IsListening = False
        done = True
    End Sub
' this sub is the thread that receive messages from other program.
    Private Sub ReceiveMessage()
                _Data = _UDPlsn.Receive(_IPEP)
            Loop Until done
        Catch ex As Exception

        End Try
    End Sub

How can I close the port in C# or ?????
Updated 31-Oct-12 0:00am
Timberbird 31-Oct-12 4:29am    
Have you tried UdpClient.Close()?
[no name] 31-Oct-12 5:09am    
Yes, but useless!!
Richard MacCutchan 31-Oct-12 6:00am    
What does that mean?
[no name] 31-Oct-12 6:10am    
I have tried UDPclient.close() but the problem stay same. The VS.NET give an error exception that I can't use same port/protocol or session in mutilple forms.
Timberbird 31-Oct-12 8:00am    
And have you checked socket state after that? Using netstat command you can check whether socket is actually closed - it often stays in CLOSE_WAIT for some time after closing, and that may be the reason you can't use the same address/port

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