Dns.BeginGetHostEntry 方法

參考

定義

命名空間:: System.Net

組件:: System.Net.NameResolution.dll

組件:: System.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

將主機名稱或 IP 位址非同步解析至 IPHostEntry 執行個體。

多載

BeginGetHostEntry(IPAddress, AsyncCallback, Object)	將 IP 位址非同步解析至 IPHostEntry 執行個體。
BeginGetHostEntry(String, AsyncCallback, Object)	將主機名稱或 IP 位址非同步解析至 IPHostEntry 執行個體。

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

來源:: Dns.cs

來源:: Dns.cs

來源:: Dns.cs

將 IP 位址非同步解析至 IPHostEntry 執行個體。

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

參數

address: IPAddress

要解析的 IP 位址。

requestCallback: AsyncCallback

AsyncCallback 委派，會於作業完成時參考要叫用的方法。

stateObject: Object

使用者定義物件，包含作業的相關資訊。作業完成時會將這個物件傳遞至 requestCallback 委派。

傳回

IAsyncResult

參考非同步要求的 IAsyncResult 執行個體。

例外狀況

ArgumentNullException

address 為 null。

SocketException

當解析 address 時，發生錯誤。

ArgumentException

address 為無效的 IP 位址。

範例

下列程式代碼範例會 BeginGetHostEntry 使用方法來將IP位址解析為 IPHostEntry 實例。

    // 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

備註

方法會 BeginGetHostEntry 以異步方式查詢 DNS 伺服器，以取得與 IP 位址相關聯的 IP 位址和別名。

注意當您在應用程式中啟用網路追蹤時，此成員會發出追蹤資訊。如需詳細資訊，請參閱 .NET Framework 中的網路追蹤。

異步 BeginGetHostEntry 操作必須藉由呼叫 EndGetHostEntry 方法來完成。一般而言，委派會叫 requestCallback 用方法。

在作業完成之前，此方法不會封鎖。若要封鎖直到作業完成為止，請使用 GetHostEntry 方法。

如需使用異步程序設計模型的詳細資訊，請參閱以異步方式呼叫同步方法

適用於

BeginGetHostEntry(String, AsyncCallback, Object)

來源:: Dns.cs

來源:: Dns.cs

來源:: Dns.cs

將主機名稱或 IP 位址非同步解析至 IPHostEntry 執行個體。

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

參數

hostNameOrAddress: String

要解析的主機名稱或 IP 位址。

requestCallback: AsyncCallback

AsyncCallback 委派，會於作業完成時參考要叫用的方法。

stateObject: Object

使用者定義物件，包含作業的相關資訊。作業完成時會將這個物件傳遞至 requestCallback 委派。

傳回

IAsyncResult

參考非同步要求的 IAsyncResult 執行個體。

例外狀況

ArgumentNullException

hostNameOrAddress 為 null。

ArgumentOutOfRangeException

hostNameOrAddress 的長度大於 255 個字元。

SocketException

當解析 hostNameOrAddress 時，發生錯誤。

ArgumentException

hostNameOrAddress 為無效的 IP 位址。

範例

下列程式代碼範例會 BeginGetHostEntry 使用方法來將IP位址解析為 IPHostEntry 實例。

    // 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

備註

方法會 BeginGetHostEntry 查詢 DNS 伺服器，以取得與主機名或 IP 位址相關聯的 IP 位址。

注意當您在應用程式中啟用網路追蹤時，此成員會發出追蹤資訊。如需詳細資訊，請參閱 .NET Framework 中的網路追蹤。

異步 BeginGetHostEntry 操作必須藉由呼叫 EndGetHostEntry 方法來完成。一般而言，委派會叫 requestCallback 用方法。

在作業完成之前，此方法不會封鎖。若要封鎖直到作業完成為止，請使用 GetHostEntry 方法。

如需使用異步程序設計模型的詳細資訊，請參閱異步呼叫同步方法。

適用於

共用方式為

Dns.BeginGetHostEntry 方法

定義

多載

BeginGetHostEntry(IPAddress, AsyncCallback, Object)

參數

傳回

例外狀況

範例

備註

適用於

BeginGetHostEntry(String, AsyncCallback, Object)

參數

傳回

例外狀況

範例

備註

適用於

其他資源