This documentation is archived and is not being maintained.

Dns.EndResolve Method

NOTE: This API is now obsolete.

Ends an asynchronous request for DNS information.

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

public static function EndResolve(
	asyncResult : IAsyncResult
) : IPHostEntry


Type: System.IAsyncResult

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

Return Value

Type: System.Net.IPHostEntry
An IPHostEntry object that contains DNS information about a host.


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.


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.

No code example is currently available or this language may not be supported.
public __gc class DnsBeginGetHostByName
   static System::Threading::ManualResetEvent* allDone = 0;
   __gc class RequestState
      IPHostEntry*  host;
         host = 0;

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

int main()
   DnsBeginGetHostByName::allDone = new ManualResetEvent(false);
   // Create an instance of the RequestState class.
   DnsBeginGetHostByName::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(S"", 
      new AsyncCallback(asyncResult, 

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

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 1.1, 1.0
Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 3.5 SP1
Obsolete (compiler warning) in 3.0
Obsolete (compiler warning) in 3.0 SP1
Obsolete (compiler warning) in 3.0 SP2
Obsolete (compiler warning) in 2.0
Obsolete (compiler warning) in 2.0 SP1
Obsolete (compiler warning) in 2.0 SP2

.NET Compact Framework

Supported in: 1.0
Obsolete (compiler warning) in 3.5
Obsolete (compiler warning) in 2.0