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Dns.BeginGetHostEntry Método

Definición

Resuelve un nombre de host o una dirección IP en una instancia de IPHostEntry de manera asincrónica.

Sobrecargas

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

Resuelve una dirección IP en una instancia de IPHostEntry de manera asincrónica.

BeginGetHostEntry(String, AsyncCallback, Object)

Resuelve un nombre de host o una dirección IP en una instancia de IPHostEntry de manera asincrónica.

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

Source:
Dns.cs
Source:
Dns.cs
Source:
Dns.cs

Resuelve una dirección IP en una instancia de IPHostEntry de manera asincrónica.

public:
 static IAsyncResult ^ BeginGetHostEntry(System::Net::IPAddress ^ address, AsyncCallback ^ requestCallback, System::Object ^ stateObject);
public static IAsyncResult BeginGetHostEntry (System.Net.IPAddress address, AsyncCallback? requestCallback, object? stateObject);
public static IAsyncResult BeginGetHostEntry (System.Net.IPAddress address, AsyncCallback requestCallback, object stateObject);
static member BeginGetHostEntry : System.Net.IPAddress * AsyncCallback * obj -> IAsyncResult
Public Shared Function BeginGetHostEntry (address As IPAddress, requestCallback As AsyncCallback, stateObject As Object) As IAsyncResult

Parámetros

address
IPAddress

Dirección IP que se va a resolver.

requestCallback
AsyncCallback

Delegado de AsyncCallback que hace referencia al método que se invocará cuando la operación se complete.

stateObject
Object

Objeto definido por el usuario que contiene información sobre la operación. Este objeto se pasa al delegado de requestCallback cuando la operación se completa.

Devoluciones

Instancia de IAsyncResult que hace referencia a la solicitud asincrónica.

Excepciones

address es null.

Se detectó un error al resolver address.

address no es una dirección IP válida.

Ejemplos

En el ejemplo de código siguiente se usa el BeginGetHostEntry método para resolver una dirección IP en una IPHostEntry instancia de .

    // Signals when the resolve has finished.
public:
    static ManualResetEvent^ GetHostEntryFinished =
        gcnew ManualResetEvent(false);

    // define the state object for the callback. 
    // use hostName to correlate calls with the proper result.
    ref class ResolveState
    {
    public:
        String^ hostName;
        IPHostEntry^ resolvedIPs;

        ResolveState(String^ host)
        {
            hostName = host;
        }

        property IPHostEntry^ IPs 
        {
            IPHostEntry^ get()
            {
                return resolvedIPs;
            }

            void set(IPHostEntry^ IPs)
            {
                resolvedIPs = IPs;
            }
        }

        property String^ host 
        {
            String^ get()
            {
                return hostName;
            }

            void set(String^ host)
            {
                hostName = host;
            }
        }
    };

    // Record the IPs in the state object for later use.
    static void GetHostEntryCallback(IAsyncResult^ ar)
    {
        ResolveState^ ioContext = (ResolveState^)(ar->AsyncState);

        ioContext->IPs = Dns::EndGetHostEntry(ar);
        GetHostEntryFinished->Set();
    }


    // Determine the Internet Protocol(IP) addresses for this 
    // host asynchronously.
public:
    static void DoGetHostEntryAsync(String^ hostName)
    {
        GetHostEntryFinished->Reset();
        ResolveState^ ioContext = gcnew ResolveState(hostName);

        Dns::BeginGetHostEntry(ioContext->host,
            gcnew AsyncCallback(GetHostEntryCallback), ioContext);
        // Wait here until the resolve completes 
        // (the callback calls .Set())
        GetHostEntryFinished->WaitOne();

        Console::WriteLine("EndGetHostEntry({0}) returns:", ioContext->host);
      
        for (int i = 0; i < ioContext->IPs->AddressList->Length; i++)
        {
            Console::WriteLine("    {0}", ioContext->IPs->AddressList[i]->ToString());
        }

//      for each (IPAddress^ address in ioContext->IPs)
//      {
//          Console::WriteLine("{0} ", address);
//      }
    }
// Signals when the resolve has finished.
public static ManualResetEvent GetHostEntryFinished =
    new ManualResetEvent(false);

// Define the state object for the callback.
// Use hostName to correlate calls with the proper result.
public class ResolveState
{
    string hostName;
    IPHostEntry resolvedIPs;

    public ResolveState(string host)
    {
        hostName = host;
    }

    public IPHostEntry IPs
    {
        get { return resolvedIPs; }
        set { resolvedIPs = value; }
    }

    public string host
    {
        get { return hostName; }
        set { hostName = value; }
    }
}

// Record the IPs in the state object for later use.
public static void GetHostEntryCallback(IAsyncResult ar)
{
    ResolveState ioContext = (ResolveState)ar.AsyncState;
    ioContext.IPs = Dns.EndGetHostEntry(ar);
    GetHostEntryFinished.Set();
}

// Determine the Internet Protocol (IP) addresses for
// this host asynchronously.
public static void DoGetHostEntryAsync(string hostname)
{
    GetHostEntryFinished.Reset();
    ResolveState ioContext= new ResolveState(hostname);

    Dns.BeginGetHostEntry(ioContext.host,
        new AsyncCallback(GetHostEntryCallback), ioContext);

    // Wait here until the resolve completes (the callback
    // calls .Set())
    GetHostEntryFinished.WaitOne();

    Console.WriteLine("EndGetHostEntry({0}) returns:", ioContext.host);

    foreach (IPAddress address in ioContext.IPs.AddressList)
    {
        Console.WriteLine($"    {address}");
    }
}
' Signals when the resolve has finished.
Dim Shared GetHostEntryFinished As ManualResetEvent = New ManualResetEvent(False)

' Define the state object for the callback. 
' Use hostName to correlate calls with the proper result.
Class ResolveState
    
    Dim hostName As String
    Dim resolvedIPs As IPHostEntry

    Public Sub New(host As String)
        hostName = host
    End Sub

    Public Property IPs AS IPHostEntry
        Get
            Return resolvedIPs
        End Get
        Set
            resolvedIPs = value
        End Set
    End Property

    Public Property host As String
        Get
            Return hostName
        End Get
        Set
            hostName = value
        End Set
    End Property

End Class

' Record the IPs in the state object for later use.
Shared Sub GetHostEntryCallback(ar As IAsyncResult)

    Dim ioContext As ResolveState = ar.AsyncState

    ioContext.IPs = Dns.EndGetHostEntry(ar)
    GetHostEntryFinished.Set()

End Sub

' Determine the Internet Protocol (IP) addresses for 
' this host asynchronously.
Shared Sub DoGetHostEntryAsync(hostname As String)
    
    GetHostEntryFinished.Reset()
    Dim ioContext As ResolveState = New ResolveState(hostname)

    Dns.BeginGetHostEntry(ioContext.host,AddressOf GetHostEntryCallback, ioContext)

    ' Wait here until the resolve completes (the callback 
    ' calls .Set())
    GetHostEntryFinished.WaitOne()

    Console.WriteLine($"EndGetHostEntry({ioContext.host}) returns:")

    Dim addresses As IPAddress() = ioContext.IPs.AddressList

    Dim index As Integer
    For index = 0 To addresses.Length - 1
        Console.WriteLine($"    {addresses(index)}")
    Next index

End Sub

Comentarios

El BeginGetHostEntry método consulta de forma asincrónica un servidor DNS para las direcciones IP y los alias asociados a una dirección IP.

Nota Este miembro emite información de seguimiento al habilitar el seguimiento de red en la aplicación. Para obtener más información, vea Seguimiento de red en .NET Framework.

La operación asincrónica BeginGetHostEntry debe completarse llamando al EndGetHostEntry método . Normalmente, el delegado invoca el requestCallback método .

Este método no se bloquea hasta que se complete la operación. Para bloquear hasta que se complete la operación, use el GetHostEntry método .

Para obtener información detallada sobre cómo usar el modelo de programación asincrónica, vea Llamar a métodos sincrónicos de forma asincrónica.

Se aplica a

BeginGetHostEntry(String, AsyncCallback, Object)

Source:
Dns.cs
Source:
Dns.cs
Source:
Dns.cs

Resuelve un nombre de host o una dirección IP en una instancia de IPHostEntry de manera asincrónica.

public:
 static IAsyncResult ^ BeginGetHostEntry(System::String ^ hostNameOrAddress, AsyncCallback ^ requestCallback, System::Object ^ stateObject);
public static IAsyncResult BeginGetHostEntry (string hostNameOrAddress, AsyncCallback? requestCallback, object? stateObject);
public static IAsyncResult BeginGetHostEntry (string hostNameOrAddress, AsyncCallback requestCallback, object stateObject);
static member BeginGetHostEntry : string * AsyncCallback * obj -> IAsyncResult
Public Shared Function BeginGetHostEntry (hostNameOrAddress As String, requestCallback As AsyncCallback, stateObject As Object) As IAsyncResult

Parámetros

hostNameOrAddress
String

Nombre de host o dirección IP que se va a resolver.

requestCallback
AsyncCallback

Delegado de AsyncCallback que hace referencia al método que se invocará cuando la operación se complete.

stateObject
Object

Objeto definido por el usuario que contiene información sobre la operación. Este objeto se pasa al delegado de requestCallback cuando la operación se completa.

Devoluciones

Instancia de IAsyncResult que hace referencia a la solicitud asincrónica.

Excepciones

hostNameOrAddress es null.

La longitud de hostNameOrAddress es mayor que 255 caracteres.

Se detectó un error al resolver hostNameOrAddress.

hostNameOrAddress no es una dirección IP válida.

Ejemplos

En el ejemplo de código siguiente se usa el BeginGetHostEntry método para resolver una dirección IP en una IPHostEntry instancia de .

    // Signals when the resolve has finished.
public:
    static ManualResetEvent^ GetHostEntryFinished =
        gcnew ManualResetEvent(false);

    // define the state object for the callback. 
    // use hostName to correlate calls with the proper result.
    ref class ResolveState
    {
    public:
        String^ hostName;
        IPHostEntry^ resolvedIPs;

        ResolveState(String^ host)
        {
            hostName = host;
        }

        property IPHostEntry^ IPs 
        {
            IPHostEntry^ get()
            {
                return resolvedIPs;
            }

            void set(IPHostEntry^ IPs)
            {
                resolvedIPs = IPs;
            }
        }

        property String^ host 
        {
            String^ get()
            {
                return hostName;
            }

            void set(String^ host)
            {
                hostName = host;
            }
        }
    };

    // Record the IPs in the state object for later use.
    static void GetHostEntryCallback(IAsyncResult^ ar)
    {
        ResolveState^ ioContext = (ResolveState^)(ar->AsyncState);

        ioContext->IPs = Dns::EndGetHostEntry(ar);
        GetHostEntryFinished->Set();
    }


    // Determine the Internet Protocol(IP) addresses for this 
    // host asynchronously.
public:
    static void DoGetHostEntryAsync(String^ hostName)
    {
        GetHostEntryFinished->Reset();
        ResolveState^ ioContext = gcnew ResolveState(hostName);

        Dns::BeginGetHostEntry(ioContext->host,
            gcnew AsyncCallback(GetHostEntryCallback), ioContext);
        // Wait here until the resolve completes 
        // (the callback calls .Set())
        GetHostEntryFinished->WaitOne();

        Console::WriteLine("EndGetHostEntry({0}) returns:", ioContext->host);
      
        for (int i = 0; i < ioContext->IPs->AddressList->Length; i++)
        {
            Console::WriteLine("    {0}", ioContext->IPs->AddressList[i]->ToString());
        }

//      for each (IPAddress^ address in ioContext->IPs)
//      {
//          Console::WriteLine("{0} ", address);
//      }
    }
// Signals when the resolve has finished.
public static ManualResetEvent GetHostEntryFinished =
    new ManualResetEvent(false);

// Define the state object for the callback.
// Use hostName to correlate calls with the proper result.
public class ResolveState
{
    string hostName;
    IPHostEntry resolvedIPs;

    public ResolveState(string host)
    {
        hostName = host;
    }

    public IPHostEntry IPs
    {
        get { return resolvedIPs; }
        set { resolvedIPs = value; }
    }

    public string host
    {
        get { return hostName; }
        set { hostName = value; }
    }
}

// Record the IPs in the state object for later use.
public static void GetHostEntryCallback(IAsyncResult ar)
{
    ResolveState ioContext = (ResolveState)ar.AsyncState;
    ioContext.IPs = Dns.EndGetHostEntry(ar);
    GetHostEntryFinished.Set();
}

// Determine the Internet Protocol (IP) addresses for
// this host asynchronously.
public static void DoGetHostEntryAsync(string hostname)
{
    GetHostEntryFinished.Reset();
    ResolveState ioContext= new ResolveState(hostname);

    Dns.BeginGetHostEntry(ioContext.host,
        new AsyncCallback(GetHostEntryCallback), ioContext);

    // Wait here until the resolve completes (the callback
    // calls .Set())
    GetHostEntryFinished.WaitOne();

    Console.WriteLine("EndGetHostEntry({0}) returns:", ioContext.host);

    foreach (IPAddress address in ioContext.IPs.AddressList)
    {
        Console.WriteLine($"    {address}");
    }
}
' Signals when the resolve has finished.
Dim Shared GetHostEntryFinished As ManualResetEvent = New ManualResetEvent(False)

' Define the state object for the callback. 
' Use hostName to correlate calls with the proper result.
Class ResolveState
    
    Dim hostName As String
    Dim resolvedIPs As IPHostEntry

    Public Sub New(host As String)
        hostName = host
    End Sub

    Public Property IPs AS IPHostEntry
        Get
            Return resolvedIPs
        End Get
        Set
            resolvedIPs = value
        End Set
    End Property

    Public Property host As String
        Get
            Return hostName
        End Get
        Set
            hostName = value
        End Set
    End Property

End Class

' Record the IPs in the state object for later use.
Shared Sub GetHostEntryCallback(ar As IAsyncResult)

    Dim ioContext As ResolveState = ar.AsyncState

    ioContext.IPs = Dns.EndGetHostEntry(ar)
    GetHostEntryFinished.Set()

End Sub

' Determine the Internet Protocol (IP) addresses for 
' this host asynchronously.
Shared Sub DoGetHostEntryAsync(hostname As String)
    
    GetHostEntryFinished.Reset()
    Dim ioContext As ResolveState = New ResolveState(hostname)

    Dns.BeginGetHostEntry(ioContext.host,AddressOf GetHostEntryCallback, ioContext)

    ' Wait here until the resolve completes (the callback 
    ' calls .Set())
    GetHostEntryFinished.WaitOne()

    Console.WriteLine($"EndGetHostEntry({ioContext.host}) returns:")

    Dim addresses As IPAddress() = ioContext.IPs.AddressList

    Dim index As Integer
    For index = 0 To addresses.Length - 1
        Console.WriteLine($"    {addresses(index)}")
    Next index

End Sub

Comentarios

El BeginGetHostEntry método consulta un servidor DNS para la dirección IP asociada a un nombre de host o una dirección IP.

Nota Este miembro emite información de seguimiento al habilitar el seguimiento de red en la aplicación. Para obtener más información, vea Seguimiento de red en .NET Framework.

La operación asincrónica BeginGetHostEntry debe completarse llamando al EndGetHostEntry método . Normalmente, el delegado invoca el requestCallback método .

Este método no se bloquea hasta que se complete la operación. Para bloquear hasta que se complete la operación, use el GetHostEntry método .

Para obtener información detallada sobre el uso del modelo de programación asincrónica, vea Llamar a métodos sincrónicos de forma asincrónica.

Se aplica a