TcpListener.Start Method ()

Starts listening for incoming connection requests.

Namespace: System.Net.Sockets
Assembly: System (in system.dll)

public void Start ()
public void Start ()
public function Start ()

Exception typeCondition

SocketException

Use the SocketException.ErrorCode property to obtain the specific error code. When you have obtained this code, you can refer to the Windows Sockets version 2 API error code documentation in MSDN for a detailed description of the error.

The Start method initializes the underlying Socket, binds it to a local endpoint, and listens for incoming connection attempts. If a connection request is received, the Start method will queue the request and continue listening for additional requests until you call the Stop method. If TcpListener receives a connection request after it has already queued the maximum number of connections, it will throw a SocketException on the client.

To remove a connection from the incoming connection queue, use either the AcceptTcpClient method or the AcceptSocket method. The AcceptTcpClient method will remove a connection from the queue and return a TcpClient that you can use to send and receive data. The AcceptSocket method will return a Socket that you can use to do the same. If your application only requires synchronous I/O, use AcceptTcpClient. For more detailed behavioral control, use AcceptSocket. Both of these methods block until a connection request is available in the queue.

Use the Stop method to close the TcpListener and stop listening. You are responsible for closing your accepted connections separately.

NoteNote

This member outputs trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following code example demonstrates how Start is used to listen for incoming client connection attempts.

public static void DoStart(TcpListener t, int backlog)
{
    // Start listening for client connections with the 
    // specified backlog.
    t.Start(backlog);
    Console.WriteLine("started listening");
}

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0
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