This documentation is archived and is not being maintained.

Dns.EndResolve Method

NOTE: This method is now obsolete.

Ends an asynchronous request for DNS information.

Namespace: System.Net
Assembly: System (in system.dll)

'Declaration
<ObsoleteAttribute("EndResolve is obsoleted for this type, please use EndGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")> _
Public Shared Function EndResolve ( _
	asyncResult As IAsyncResult _
) As IPHostEntry
'Usage
Dim asyncResult As IAsyncResult
Dim returnValue As IPHostEntry

returnValue = Dns.EndResolve(asyncResult)
/** @attribute ObsoleteAttribute("EndResolve is obsoleted for this type, please use EndGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202") */ 
public static IPHostEntry EndResolve (
	IAsyncResult asyncResult
)
ObsoleteAttribute("EndResolve is obsoleted for this type, please use EndGetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202") 
public static function EndResolve (
	asyncResult : IAsyncResult
) : IPHostEntry
Not applicable.

Parameters

asyncResult

An IAsyncResult instance that is returned by a call to the BeginResolve method.

Return Value

An IPHostEntry object that contains DNS information about a host.

Exception typeCondition

ArgumentNullException

asyncResult is a null reference (Nothing in Visual Basic).

This method blocks until the operation is complete.

To perform this operation synchronously, use the Resolve method.

NoteNote:

This member emits trace information when you enable network tracing in your application. For more information, see Network Tracing.

The following example ends an asynchronous request for DNS host information.

Class DnsBeginGetHostByName
    
    Class RequestState
        Public host As IPHostEntry
        
        Public Sub New()
            host = Nothing
        End Sub 'New
    End Class 'RequestState
    
    
    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 'Main
    
    
    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 'RespCallback

class DnsBeginGetHostByName
{
    public static System.Threading.ManualResetEvent allDone = null;

    static class RequestState
    {
        public IPHostEntry host;

        public RequestState()
        {
            host = null;
        } //RequestState
    } //RequestState

    public static void main(String[] args)
    {
        allDone = new ManualResetEvent(false);        
        
        // Create an instance of the RequestState class.
        RequestState myRequestState = new 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", 
            new AsyncCallback(RespCallback), myRequestState);

        // Wait until asynchronous call completes.
        allDone.WaitOne();
        Console.WriteLine("Host name : " + myRequestState.host.get_HostName());
        Console.WriteLine("\nIP address list : ");
        for (int index = 0; index < myRequestState.host.
            get_AddressList().length; index++) {
            Console.WriteLine(myRequestState.host.get_AddressList().
                get_Item(index));
        }
        Console.WriteLine("\nAliases : ");
        for (int index = 0; index < myRequestState.host.get_Aliases().
            length; index++) {
            Console.WriteLine(myRequestState.host.get_Aliases().
                get_Item(index));
        }
    } //main

    private static void RespCallback(IAsyncResult ar)
    {
        try {
            // Convert the IAsyncResult object to a RequestState object.
            RequestState tempRequestState = (RequestState)ar.get_AsyncState();

            // End the asynchronous request.
            tempRequestState.host = Dns.EndResolve(ar);
            allDone.Set();
        }
        catch (ArgumentNullException e) {
            Console.WriteLine("ArgumentNullException caught!!!");
            Console.WriteLine("Source : " + e.get_Source());
            Console.WriteLine("Message : " + e.get_Message());
        }
        catch (System.Exception e) {
            Console.WriteLine("Exception caught!!!");
            Console.WriteLine("Source : " + e.get_Source());
            Console.WriteLine("Message : " + e.get_Message());
        }
    } //RespCallback
} //DnsBeginGetHostByName

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 1.0, 1.1, 2.0
Obsolete (compiler warning) in 3.0

.NET Compact Framework

Supported in: 1.0
Obsolete (compiler warning) in 2.0

Reference

Dns Class
Dns Members
System.Net Namespace

Other Resources

Asynchronous Calls
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