socket usage permission

mahraja

Hi I recieve this exception: "Only one usage of each socket address (protocol/network address/port) is normally permitted" I should get several files from an ftp server. I implemented it by sockets so: create the datasocket, recieve the file and then close data socket. But the next time I do this for another file(create data socket with Endpoint (the same local address/another port)), i recieve this exception message when Binding the socket. Can anyone tell me why? And the way to solve that? (the code, if necessary)

public void download(string remFileName, string locFileName)
{
if (!logined)
{
login();
}

setBinaryMode(true);
Console.WriteLine("Downloading file " + remFileName + " from " + remoteHost + "/" + remotePath);

if (locFileName.Equals(""))
{
    locFileName = remFileName;
}

if (!File.Exists(locFileName))
{
    Stream st = File.Create(locFileName);
    st.Close();
}

FileStream output = new FileStream(locFileName, FileMode.Open);

createDataSocket(true);
if (dataSocket != null)
{
    throw new SocketException();
}
//\*\*\*\*
sendCommand("RETR " + remFileName);

if (!(retValue == 150 || retValue == 125))
{
    throw new IOException(reply.Substring(4));
}
//\*\*\*\*

dataSocket = listeningSocket.Accept();
listeningSocket.Close();
listeningSocket = null;
if (dataSocket == null)
{
    throw new Exception("Winsock error: " +
            Convert.ToString(System.Runtime.InteropServices.Marshal.GetLastWin32Error()));
}

while (true)
{
    bytes = dataSocket.Receive(buffer, buffer.Length, 0);
    output.Write(buffer, 0, bytes);

    if (bytes <= 0)
    {
        break;
    }
}

output.Close();

if (dataSocket.Connected)
{
    //dataSocket.Shutdown(SocketShutdown.Both);
    dataSocket.Close();
    dataSocket = null;
}

Console.WriteLine("");

readReply();

if (!(retValue == 226 || retValue == 250))
{
    throw new IOException(reply.Substring(4));
}

}

public void createDataSocket(bool flag)
{
try
{
listeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
}
catch (Exception e)
{
ftpLog(e.Message);
throw new IOException(e.Message);
}

string localAddress = clientSocket.LocalEndPoint.To