Поделиться через


Dns.BeginResolve(String, AsyncCallback, Object) Метод

Определение

Внимание!

BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. https://go.microsoft.com/fwlink/?linkid=14202

Внимание!

BeginResolve has been deprecated. Use BeginGetHostEntry instead.

Внимание!

BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202

Начинает асинхронный запрос для разрешения DNS-имени узла или IP-адреса в экземпляр IPAddress.

public:
 static IAsyncResult ^ BeginResolve(System::String ^ hostName, AsyncCallback ^ requestCallback, System::Object ^ stateObject);
[System.Obsolete("BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. https://go.microsoft.com/fwlink/?linkid=14202")]
public static IAsyncResult BeginResolve (string hostName, AsyncCallback? requestCallback, object? stateObject);
[System.Obsolete("BeginResolve has been deprecated. Use BeginGetHostEntry instead.")]
public static IAsyncResult BeginResolve (string hostName, AsyncCallback? requestCallback, object? stateObject);
[System.Obsolete("BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")]
public static IAsyncResult BeginResolve (string hostName, AsyncCallback requestCallback, object stateObject);
[System.Obsolete("BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. https://go.microsoft.com/fwlink/?linkid=14202")]
public static IAsyncResult BeginResolve (string hostName, AsyncCallback requestCallback, object stateObject);
public static IAsyncResult BeginResolve (string hostName, AsyncCallback requestCallback, object stateObject);
[<System.Obsolete("BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. https://go.microsoft.com/fwlink/?linkid=14202")>]
static member BeginResolve : string * AsyncCallback * obj -> IAsyncResult
[<System.Obsolete("BeginResolve has been deprecated. Use BeginGetHostEntry instead.")>]
static member BeginResolve : string * AsyncCallback * obj -> IAsyncResult
[<System.Obsolete("BeginResolve is obsoleted for this type, please use BeginGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")>]
static member BeginResolve : string * AsyncCallback * obj -> IAsyncResult
static member BeginResolve : string * AsyncCallback * obj -> IAsyncResult
Public Shared Function BeginResolve (hostName As String, requestCallback As AsyncCallback, stateObject As Object) As IAsyncResult

Параметры

hostName
String

DNS-имя узла.

requestCallback
AsyncCallback

Делегат AsyncCallback, ссылающийся на метод, вызываемый по завершении данной операции.

stateObject
Object

Пользовательский объект, содержащий сведения об операции. Этот объект передается делегату requestCallback по завершении операции.

Возвращаемое значение

Экземпляр IAsyncResult, который ссылается на асинхронный запрос.

Атрибуты

Исключения

hostName имеет значение null.

Вызывающий код не имеет разрешения на доступ к сведениям DNS.

Примеры

В следующем примере используется BeginResolve для разрешения имени узла DNS в IPAddress.

public ref class DnsBeginGetHostByName
{
public:
   static System::Threading::ManualResetEvent^ allDone = nullptr;
   ref class RequestState
   {
   public:
      IPHostEntry^ host;
      RequestState()
      {
         host = nullptr;
      }
   };

   static void RespCallback( IAsyncResult^ ar )
   {
      try
      {
         // Convert the IAsyncResult* Object* to a RequestState Object*.
         RequestState^ tempRequestState = dynamic_cast<RequestState^>(ar->AsyncState);
         
         // End the asynchronous request.
         tempRequestState->host = Dns::EndResolve( ar );
         allDone->Set();
      }
      catch ( ArgumentNullException^ e ) 
      {
         Console::WriteLine( "ArgumentNullException caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( "Exception caught!!!" );
         Console::WriteLine( "Source : {0}", e->Source );
         Console::WriteLine( "Message : {0}", e->Message );
      }
   }
};

int main()
{
   DnsBeginGetHostByName::allDone = gcnew ManualResetEvent( false );
   
   // Create an instance of the RequestState class.
   DnsBeginGetHostByName::RequestState^ myRequestState =
      gcnew DnsBeginGetHostByName::RequestState;
   
   // Begin an asynchronous request for information like host name, IP addresses, or
   // aliases for specified the specified URI.
   IAsyncResult^ asyncResult = Dns::BeginResolve( "www.contoso.com",
      gcnew AsyncCallback( DnsBeginGetHostByName::RespCallback ), myRequestState );
   
   // Wait until asynchronous call completes.
   DnsBeginGetHostByName::allDone->WaitOne();
   Console::WriteLine( "Host name : {0}", myRequestState->host->HostName );
   Console::WriteLine( "\nIP address list : " );
   for ( int index = 0; index < myRequestState->host->AddressList->Length; index++ )
      Console::WriteLine( myRequestState->host->AddressList[ index ] );
   Console::WriteLine( "\nAliases : " );
   for ( int index = 0; index < myRequestState->host->Aliases->Length; index++ )
      Console::WriteLine( myRequestState->host->Aliases[ index ] );
}
class DnsBeginGetHostByName
{
   public static System.Threading.ManualResetEvent allDone = null;

   class RequestState
   {
      public IPHostEntry host;
      public RequestState()
      {
         host = null;
      }
   }

   public static void Main()
   {
     allDone = new ManualResetEvent(false);
     // Create an instance of the RequestState class.
     RequestState myRequestState = new RequestState();

     // Begin an asynchronous request for information like host name, IP addresses, or
     // aliases for specified the specified URI.
     IAsyncResult asyncResult = Dns.BeginResolve("www.contoso.com", new AsyncCallback(RespCallback), myRequestState );

     // Wait until asynchronous call completes.
     allDone.WaitOne();
     Console.WriteLine("Host name : " + myRequestState.host.HostName);
     Console.WriteLine("\nIP address list : ");
     for(int index=0; index < myRequestState.host.AddressList.Length; index++)
     {
       Console.WriteLine(myRequestState.host.AddressList[index]);
     }
     Console.WriteLine("\nAliases : ");
     for(int index=0; index < myRequestState.host.Aliases.Length; index++)
     {
       Console.WriteLine(myRequestState.host.Aliases[index]);
     }
   }

   private static void RespCallback(IAsyncResult ar)
   {
     try
     {
       // Convert the IAsyncResult object to a RequestState object.
       RequestState tempRequestState = (RequestState)ar.AsyncState;
       // End the asynchronous request.
       tempRequestState.host = Dns.EndResolve(ar);
       allDone.Set();
     }
       catch(ArgumentNullException e)
     {
       Console.WriteLine("ArgumentNullException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
     catch(Exception e)
     {
       Console.WriteLine("Exception caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
     }
   }
}
Class DnsBeginGetHostByName
    
    Class RequestState
        Public host As IPHostEntry
        
        Public Sub New()
            host = Nothing
        End Sub
    End Class
    
    
    Public Shared Sub Main()
     Try
        ' Create an instance of the RequestState class.
        Dim myRequestState As New RequestState()
        
        ' Begin an asynchronous request for information such as the host name, IP addresses, 
        ' or aliases for the specified URI.
        Dim asyncResult As IAsyncResult = CType(Dns.BeginResolve("www.contoso.com", AddressOf RespCallback, myRequestState),IAsyncResult)

        ' Wait until asynchronous call completes.
        While asyncResult.IsCompleted <> True
        End While
        
        Console.WriteLine(("Host name : " + myRequestState.host.HostName))
        Console.WriteLine(ControlChars.Cr + "IP address list : ")
        Dim index As Integer
        For index = 0 To myRequestState.host.AddressList.Length - 1
            Console.WriteLine(myRequestState.host.AddressList(index))
        Next index
        Console.WriteLine(ControlChars.Cr + "Aliases : ")

        For index = 0 To myRequestState.host.Aliases.Length - 1
            Console.WriteLine(myRequestState.host.Aliases(index))
        Next index
    catch e as Exception
            Console.WriteLine("Exception caught!!!")
            Console.WriteLine(("Source : " + e.Source))
            Console.WriteLine(("Message : " + e.Message))
    End Try
    End Sub
    
    
    Private Shared Sub RespCallback(ar As IAsyncResult)
        Try
            ' Convert the IAsyncResult object to a RequestState object.
            Dim tempRequestState As RequestState = CType(ar.AsyncState, RequestState)

            ' End the asynchronous request.
            tempRequestState.host = Dns.EndResolve(ar)
            Catch e As ArgumentNullException
            Console.WriteLine("ArgumentNullException caught!!!")
            Console.WriteLine(("Source : " + e.Source))
            Console.WriteLine(("Message : " + e.Message))
            Catch e As Exception
            Console.WriteLine("Exception caught!!!")
            Console.WriteLine(("Source : " + e.Source))
            Console.WriteLine(("Message : " + e.Message))
        End Try
    End Sub

Комментарии

Асинхронная BeginResolve операция должна быть завершена путем вызова EndResolve метода . Как правило, метод вызывается делегатом requestCallback .

Этот метод не блокируется до завершения операции. Чтобы заблокировать до завершения операции, используйте Resolve метод .

Дополнительные сведения об использовании асинхронной модели программирования см. в разделе Вызов синхронных методов асинхронно.

Примечание

Этот элемент выдает сведения трассировки при включении трассировки сети в приложении. Дополнительные сведения см. в статье Трассировка сети в .NET Framework.

Применяется к

См. также раздел