TcpListener Class
Listens for connections from TCP network clients.
Assembly: System (in System.dll)
The TcpListener type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | TcpListener(Int32) | Obsolete. Initializes a new instance of the TcpListener class that listens on the specified port. |
![]() | TcpListener(IPEndPoint) | Initializes a new instance of the TcpListener class with the specified local endpoint. |
![]() | TcpListener(IPAddress, Int32) | Initializes a new instance of the TcpListener class that listens for incoming connection attempts on the specified local IP address and port number. |
| Name | Description | |
|---|---|---|
![]() | Active | Gets a value that indicates whether TcpListener is actively listening for client connections. |
![]() | ExclusiveAddressUse | Gets or sets a Boolean value that specifies whether the TcpListener allows only one underlying socket to listen to a specific port. |
![]() | LocalEndpoint | Gets the underlying EndPoint of the current TcpListener. |
![]() | Server | Gets the underlying network Socket. |
| Name | Description | |
|---|---|---|
![]() | AcceptSocket | Accepts a pending connection request. |
![]() | AcceptTcpClient | Accepts a pending connection request |
![]() | AllowNatTraversal | Enables or disables Network Address Translation (NAT) traversal on a TcpListener instance. |
![]() | BeginAcceptSocket | Begins an asynchronous operation to accept an incoming connection attempt. |
![]() | BeginAcceptTcpClient | Begins an asynchronous operation to accept an incoming connection attempt. |
![]() | EndAcceptSocket | Asynchronously accepts an incoming connection attempt and creates a new Socket to handle remote host communication. |
![]() | EndAcceptTcpClient | Asynchronously accepts an incoming connection attempt and creates a new TcpClient to handle remote host communication. |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | Pending | Determines if there are pending connection requests. |
![]() | Start() | Starts listening for incoming connection requests. |
![]() | Start(Int32) | Starts listening for incoming connection requests with a maximum number of pending connection. |
![]() | Stop | Closes the listener. |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
The TcpListener class provides simple methods that listen for and accept incoming connection requests in blocking synchronous mode. You can use either a TcpClient or a Socket to connect with a TcpListener. Create a TcpListener using an IPEndPoint, a Local IP address and port number, or just a port number. Specify Any for the local IP address and 0 for the local port number if you want the underlying service provider to assign those values for you. If you choose to do this, you can use the LocalEndpoint property to identify the assigned information, after the socket has connected.
Use the Start method to begin listening for incoming connection requests. Start will queue incoming connections until you either call the Stop method or it has queued MaxConnections. Use either AcceptSocket or AcceptTcpClient to pull a connection from the incoming connection request queue. These two methods will block. If you want to avoid blocking, you can use the Pending method first to determine if connection requests are available in the queue.
Call the Stop method to close the TcpListener.
Note |
|---|
The Stop method does not close any accepted connections. You are responsible for closing these separately. |
The following code example creates a TcpListener.
#using <System.dll> using namespace System; using namespace System::IO; using namespace System::Net; using namespace System::Net::Sockets; using namespace System::Text; using namespace System::Threading; void main() { try { // Set the TcpListener on port 13000. Int32 port = 13000; IPAddress^ localAddr = IPAddress::Parse( "127.0.0.1" ); // TcpListener* server = new TcpListener(port); TcpListener^ server = gcnew TcpListener( localAddr,port ); // Start listening for client requests. server->Start(); // Buffer for reading data array<Byte>^bytes = gcnew array<Byte>(256); String^ data = nullptr; // Enter the listening loop. while ( true ) { Console::Write( "Waiting for a connection... " ); // Perform a blocking call to accept requests. // You could also user server.AcceptSocket() here. TcpClient^ client = server->AcceptTcpClient(); Console::WriteLine( "Connected!" ); data = nullptr; // Get a stream Object* for reading and writing NetworkStream^ stream = client->GetStream(); Int32 i; // Loop to receive all the data sent by the client. while ( i = stream->Read( bytes, 0, bytes->Length ) ) { // Translate data bytes to a ASCII String*. data = Text::Encoding::ASCII->GetString( bytes, 0, i ); Console::WriteLine( "Received: {0}", data ); // Process the data sent by the client. data = data->ToUpper(); array<Byte>^msg = Text::Encoding::ASCII->GetBytes( data ); // Send back a response. stream->Write( msg, 0, msg->Length ); Console::WriteLine( "Sent: {0}", data ); } // Shutdown and end connection client->Close(); } } catch ( SocketException^ e ) { Console::WriteLine( "SocketException: {0}", e ); } Console::WriteLine( "\nHit enter to continue..." ); Console::Read(); }
See TcpClient for a client example.
- SocketPermission
to establish an outgoing connection or accept an incoming request.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
