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Dns.BeginGetHostEntry Metoda

Definice

Asynchronně přeloží název hostitele nebo IP adresu na IPHostEntry instanci.

Přetížení

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

Asynchronně přeloží IP adresu na IPHostEntry instanci.

BeginGetHostEntry(String, AsyncCallback, Object)

Asynchronně přeloží název hostitele nebo IP adresu na IPHostEntry instanci.

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

Zdroj:
Dns.cs
Zdroj:
Dns.cs
Zdroj:
Dns.cs

Asynchronně přeloží IP adresu na IPHostEntry instanci.

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

Parametry

address
IPAddress

IP adresa, která se má přeložit.

requestCallback
AsyncCallback

Delegát AsyncCallback , který odkazuje na metodu, která se má vyvolat po dokončení operace.

stateObject
Object

Objekt definovaný uživatelem, který obsahuje informace o operaci. Po dokončení operace se tento objekt předá requestCallback delegátu.

Návraty

Instance IAsyncResult , která odkazuje na asynchronní požadavek.

Výjimky

address je null.

Při řešení chyby dojde k addresschybě .

address je neplatná IP adresa.

Příklady

Následující příklad kódu používá metodu BeginGetHostEntry k překladu IP adresy na IPHostEntry instanci.

    // 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

Poznámky

Metoda BeginGetHostEntry asynchronně dotazuje server DNS na IP adresy a aliasy přidružené k IP adrese.

Poznámka Tento člen generuje informace o trasování, když povolíte trasování sítě ve vaší aplikaci. Další informace najdete v tématu Trasování sítě v rozhraní .NET Framework.

Asynchronní BeginGetHostEntry operace musí být dokončena voláním EndGetHostEntry metody . Obvykle je metoda vyvolána delegátem requestCallback .

Tato metoda neblokuje, dokud není operace dokončena. Pokud chcete blokovat, dokud se operace dokončí, použijte metodu GetHostEntry .

Podrobné informace o použití asynchronního programovacího modelu najdete v tématu Asynchronní volání synchronních metod.

Platí pro

BeginGetHostEntry(String, AsyncCallback, Object)

Zdroj:
Dns.cs
Zdroj:
Dns.cs
Zdroj:
Dns.cs

Asynchronně přeloží název hostitele nebo IP adresu na IPHostEntry instanci.

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

Parametry

hostNameOrAddress
String

Název hostitele nebo IP adresa, které se mají přeložit.

requestCallback
AsyncCallback

Delegát AsyncCallback , který odkazuje na metodu, která se má vyvolat po dokončení operace.

stateObject
Object

Objekt definovaný uživatelem, který obsahuje informace o operaci. Po dokončení operace se tento objekt předá requestCallback delegátu.

Návraty

Instance IAsyncResult , která odkazuje na asynchronní požadavek.

Výjimky

hostNameOrAddress je null.

Délka hostNameOrAddress je větší než 255 znaků.

Při řešení chyby dojde k hostNameOrAddresschybě .

hostNameOrAddress je neplatná IP adresa.

Příklady

Následující příklad kódu používá metodu BeginGetHostEntry k překladu IP adresy na IPHostEntry instanci.

    // 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

Poznámky

Metoda BeginGetHostEntry se dotazuje serveru DNS na IP adresu přidruženou k názvu hostitele nebo IP adrese.

Poznámka Tento člen generuje informace o trasování, když povolíte trasování sítě ve vaší aplikaci. Další informace najdete v tématu Trasování sítě v rozhraní .NET Framework.

Asynchronní BeginGetHostEntry operace musí být dokončena voláním EndGetHostEntry metody . Obvykle je metoda vyvolána delegátem requestCallback .

Tato metoda neblokuje, dokud není operace dokončena. Pokud chcete blokovat, dokud se operace dokončí, použijte metodu GetHostEntry .

Podrobné informace o použití asynchronního programovacího modelu najdete v tématu Asynchronní volání synchronních metod.

Platí pro