TcpListener.BeginAcceptSocket(AsyncCallback, Object) Method

Definition

Namespace:

System.Net.Sockets

Assembly:

System.Net.Sockets.dll

Begins an asynchronous operation to accept an incoming connection attempt.

public:
 IAsyncResult ^ BeginAcceptSocket(AsyncCallback ^ callback, System::Object ^ state);

public IAsyncResult BeginAcceptSocket (AsyncCallback? callback, object? state);

member this.BeginAcceptSocket : AsyncCallback * obj -> IAsyncResult

Public Function BeginAcceptSocket (callback As AsyncCallback, state As Object) As IAsyncResult

Parameters

callback

AsyncCallback

An AsyncCallback delegate that references the method to invoke when the operation is complete.

state

Object

A user-defined object containing information about the accept operation. This object is passed to the callback delegate when the operation is complete.

Returns

IAsyncResult

An IAsyncResult that references the asynchronous creation of the Socket.

Exceptions

SocketException

An error occurred while attempting to access the socket.

ObjectDisposedException

The Socket has been closed.

Examples

The following code example demonstrates the use of the BeginAcceptSocket method to create and connect a socket. The callback delegate calls the EndAcceptSocket method to end the asynchronous request.

    // Thread signal.
public:
    static ManualResetEvent^ ClientConnected;

    // Accept one client connection asynchronously.
public:
    static void DoBeginAcceptSocket(TcpListener^ listener)
    {
        // Set the event to nonsignaled state.
        ClientConnected->Reset();

        // Start to listen for connections from a client.
        Console::WriteLine("Waiting for a connection...");

        // Accept the connection.
        // BeginAcceptSocket() creates the accepted socket.
        listener->BeginAcceptSocket(
            gcnew AsyncCallback(DoAcceptSocketCallback), listener);
        // Wait until a connection is made and processed before
        // continuing.
        ClientConnected->WaitOne();
    }

    // Process the client connection.
public:
    static void DoAcceptSocketCallback(IAsyncResult^ result)
    {
        // Get the listener that handles the client request.
        TcpListener^ listener = (TcpListener^) result->AsyncState;

        // End the operation and display the received data on the
        //console.
        Socket^ clientSocket = listener->EndAcceptSocket(result);

        // Process the connection here. (Add the client to a
        // server table, read data, etc.)
        Console::WriteLine("Client connected completed");

        // Signal the calling thread to continue.
        ClientConnected->Set();
    }

// Thread signal.
public static ManualResetEvent clientConnected =
    new ManualResetEvent(false);

// Accept one client connection asynchronously.
public static void DoBeginAcceptSocket(TcpListener listener)
{
    // Set the event to nonsignaled state.
    clientConnected.Reset();

    // Start to listen for connections from a client.
    Console.WriteLine("Waiting for a connection...");

    // Accept the connection.
    // BeginAcceptSocket() creates the accepted socket.
    listener.BeginAcceptSocket(
        new AsyncCallback(DoAcceptSocketCallback), listener);
    // Wait until a connection is made and processed before
    // continuing.
    clientConnected.WaitOne();
}

// Process the client connection.
public static void DoAcceptSocketCallback(IAsyncResult ar)
{
    // Get the listener that handles the client request.
    TcpListener listener = (TcpListener) ar.AsyncState;

    // End the operation and display the received data on the
    //console.
    Socket clientSocket = listener.EndAcceptSocket(ar);

    // Process the connection here. (Add the client to a
    // server table, read data, etc.)
    Console.WriteLine("Client connected completed");

    // Signal the calling thread to continue.
    clientConnected.Set();
}

' Thread signal.
Public Shared clientConnected As New ManualResetEvent(False)


' Accept one client connection asynchronously.
Public Shared Sub DoBeginAcceptSocket(listener As TcpListener)
   ' Set the event to nonsignaled state.
   clientConnected.Reset()
   
   ' Start to listen for connections from a client.
   Console.WriteLine("Waiting for a connection...")
   
   ' Accept the connection. 
   ' BeginAcceptSocket() creates the accepted socket.
   listener.BeginAcceptSocket(New AsyncCallback(AddressOf DoAcceptSocketCallback), listener)
   ' Wait until a connection is made and processed before 
   ' continuing.
   clientConnected.WaitOne()
End Sub


' Process the client connection.
Public Shared Sub DoAcceptSocketCallback(ar As IAsyncResult)
   ' Get the listener that handles the client request.
   Dim listener As TcpListener = CType(ar.AsyncState, TcpListener)
   
   ' End the operation and display the received data on the
   'console.
   Dim clientSocket As Socket = listener.EndAcceptSocket(ar)
   
   ' Process the connection here. (Add the client to a 
   ' server table, read data, etc.)
   Console.WriteLine("Client connected completed")
   
   ' Signal the calling thread to continue.
   clientConnected.Set()
End Sub

Remarks

The asynchronous BeginAcceptSocket operation must be completed by calling the EndAcceptSocket method. Typically, the method is invoked by the callback delegate.

This method does not block until the operation completes. To block until the operation completes, use the AcceptSocket method.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously.

Note

You can call the RemoteEndPoint property of the returned Socket to identify the remote host's network address and port number.

Note

If you receive a SocketException, use the SocketException.ErrorCode property to obtain the specific error code and refer to the Windows Sockets version 2 API error code documentation for a detailed description of the error.

Note

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