TcpListener.Pending Metodo

Definizione

Spazio dei nomi:

System.Net.Sockets

Assembly:

System.Net.Sockets.dll

Origine:

TCPListener.cs

Determina se sono presenti richieste di connessione in sospeso.

public:
 bool Pending();

public bool Pending ();

member this.Pending : unit -> bool

Public Function Pending () As Boolean

Restituisce

Boolean

true se vi sono connessioni in sospeso; in caso contrario, false.

Eccezioni

InvalidOperationException

Il listener non è stato avviato con una chiamata a Start().

Esempio

Nell'esempio di codice seguente viene controllato il Pending metodo . Se una richiesta di connessione è in attesa di essere accettata, viene effettuata una chiamata al AcceptTcpClient metodo .

try
{
   // Use the Pending method to poll the underlying socket instance for client connection requests.
   TcpListener^ tcpListener = gcnew TcpListener( portNumber );
   tcpListener->Start();

   if ( !tcpListener->Pending() )
   {
      Console::WriteLine( "Sorry, no connection requests have arrived" );
   }
   else
   {
      //Accept the pending client connection and return a TcpClient object^ initialized for communication.
      TcpClient^ tcpClient = tcpListener->AcceptTcpClient();
      
      // Using the RemoteEndPoint property.
      Console::WriteLine( "I am listening for connections on {0} on port number {1}",
         IPAddress::Parse( ( (IPEndPoint^)(tcpListener->LocalEndpoint) )->Address->ToString() ),
         ( (IPEndPoint^)(tcpListener->LocalEndpoint) )->Port );

const int portNumber = 13;

try
{
    // Use the Pending method to poll the underlying socket instance for client connection requests.
    IPAddress ipAddress = Dns.Resolve("localhost").AddressList[0];
    TcpListener tcpListener = new TcpListener(ipAddress, portNumber);
    tcpListener.Start();

    if (!tcpListener.Pending())
    {
        Console.WriteLine("Sorry, no connection requests have arrived");
    }
    else
    {
        //Accept the pending client connection and return a TcpClient object initialized for communication.
        TcpClient tcpClient = tcpListener.AcceptTcpClient();
        // Using the RemoteEndPoint property.
        Console.WriteLine("I am listening for connections on " +
            IPAddress.Parse(((IPEndPoint)tcpListener.LocalEndpoint).Address.ToString()) +
            "on port number " + ((IPEndPoint)tcpListener.LocalEndpoint).Port.ToString());

        //Close the tcpListener and tcpClient instances
        tcpClient.Close();
    }

    tcpListener.Stop();
}
catch (Exception e)
{
    Console.WriteLine(e.ToString());
}

Try

   Dim ipAddress As IPAddress = Dns.Resolve("localhost").AddressList(0)
  Dim tcpListener As New TcpListener(ipAddress, portNumber)
  tcpListener.Start()
  
   ' Use the Pending method to poll the underlying socket instance for client connection requests.
   If Not tcpListener.Pending() Then
      
      Console.WriteLine("Sorry, no connection requests have arrived")
   
   Else
      
      'Accept the pending client connection and return a TcpClient object initialized for communication.
      Dim tcpClient As TcpClient = tcpListener.AcceptTcpClient()
      ' Using the RemoteEndPoint property.
      Console.Write("I am listening for connections on ")
      Console.Writeline(IPAddress.Parse(CType(tcpListener.LocalEndpoint, IPEndPoint).Address.ToString())) 
      Console.Write("on port number ")
      Console.Write(CType(tcpListener.LocalEndpoint, IPEndPoint).Port.ToString())

Commenti

Questo metodo non bloccante determina se sono presenti richieste di connessione in sospeso. Poiché i metodi e bloccano l'esecuzione AcceptSocket finché il Start metodo non ha accodato una richiesta di connessione in ingresso, il Pending metodo può essere usato per determinare se le connessioni sono disponibili prima di tentare di accettarle.AcceptTcpClient

Vedi anche

• Start()
• AcceptSocket()
• AcceptTcpClient()