.NET Framework Class Library
Dns..::.Resolve Method

NOTE: This API is now obsolete.

Resolves a DNS host name or IP address to an IPHostEntry instance.

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

Visual Basic (Declaration)
<ObsoleteAttribute("Resolve is obsoleted for this type, please use GetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")> _
Public Shared Function Resolve ( _
    hostName As String _
) As IPHostEntry
Visual Basic (Usage)
Dim hostName As String
Dim returnValue As IPHostEntry

returnValue = Dns.Resolve(hostName)
C#
[ObsoleteAttribute("Resolve is obsoleted for this type, please use GetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")]
public static IPHostEntry Resolve(
    string hostName
)
Visual C++
[ObsoleteAttribute(L"Resolve is obsoleted for this type, please use GetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")]
public:
static IPHostEntry^ Resolve(
    String^ hostName
)
JScript
public static function Resolve(
    hostName : String
) : IPHostEntry

Parameters

hostName
Type: System..::.String
A DNS-style host name or IP address.

Return Value

Type: System.Net..::.IPHostEntry
An IPHostEntry instance that contains address information about the host specified in hostName.
Exceptions

ExceptionCondition
ArgumentNullException

hostName is nullNothingnullptra null reference (Nothing in Visual Basic).

ArgumentOutOfRangeException

The length of hostName is greater than 126 characters.

SocketException

An error is encountered when resolving hostName.

Remarks

The Resolve method queries a DNS server for the IP address associated with a host name or IP address.

When hostName is a DNS-style host name associated with multiple IP addresses, only the first IP address that resolves to that host name is returned.

NoteNote:

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

Examples

The following example uses the Resolve method to resolve an IP address to an IPHostEntry instance.

Visual Basic
Try
    ' Call the Resolve method passing a DNS style host name or an IP address in 
    ' dotted-quad notation (for example, "www.contoso.com" or "207.46.131.199") to 
    ' obtain an IPHostEntry instance that contains address information for the 
    ' specified host.
    Dim hostInfo As IPHostEntry = Dns.Resolve(hostString)
    ' Get the IP address list that resolves to the host names contained in the Alias 
    ' property.
    Dim address As IPAddress() = hostInfo.AddressList
    ' Get the alias names of the addresses in the IP address list.
    Dim [alias] As [String]() = hostInfo.Aliases

    Console.WriteLine(("Host name : " + hostInfo.HostName))
    Console.WriteLine(ControlChars.Cr + "Aliases : ")
    Dim index As Integer
    For index = 0 To [alias].Length - 1
        Console.WriteLine([alias](index))
    Next index
    Console.WriteLine(ControlChars.Cr + "IP Address list :")

    For index = 0 To address.Length - 1
        Console.WriteLine(address(index))
    Next index
Catch e As SocketException
    Console.WriteLine("SocketException caught!!!")
    Console.WriteLine(("Source : " + e.Source))
    Console.WriteLine(("Message : " + e.Message))
Catch e As ArgumentNullException
    Console.WriteLine("ArgumentNullException caught!!!")
    Console.WriteLine(("Source : " + e.Source))
    Console.WriteLine(("Message : " + e.Message))
Catch e As NullReferenceException
    Console.WriteLine("NullReferenceException 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
C#
     try {
         IPHostEntry hostInfo = Dns.Resolve(hostString);
         // Get the IP address list that resolves to the host names contained in the 
         // Alias property.
         IPAddress[] address = hostInfo.AddressList;
         // Get the alias names of the addresses in the IP address list.
         String[] alias = hostInfo.Aliases;

         Console.WriteLine("Host name : " + hostInfo.HostName);
         Console.WriteLine("\nAliases : ");
         for(int index=0; index < alias.Length; index++) {
           Console.WriteLine(alias[index]);
         } 
         Console.WriteLine("\nIP Address list :");
         for(int index=0; index < address.Length; index++) {
            Console.WriteLine(address[index]);
         }
      }
      catch(SocketException e) 
      {
         Console.WriteLine("SocketException caught!!!");
         Console.WriteLine("Source : " + e.Source);
         Console.WriteLine("Message : " + e.Message);
      }
      catch(ArgumentNullException e)
      {
     Console.WriteLine("ArgumentNullException caught!!!");
         Console.WriteLine("Source : " + e.Source);
         Console.WriteLine("Message : " + e.Message);
      }
      catch(NullReferenceException e)
      {
          Console.WriteLine("NullReferenceException caught!!!");
          Console.WriteLine("Source : " + e.Source);
          Console.WriteLine("Message : " + e.Message);
      }
      catch(Exception e)
      {
          Console.WriteLine("Exception caught!!!");
          Console.WriteLine("Source : " + e.Source);
          Console.WriteLine("Message : " + e.Message);
      }
Visual C++
try
{
   IPHostEntry^ hostInfo = Dns::Resolve( hostString );

   // Get the IP address list that resolves to the host names contained in the
   // Alias property.
   array<IPAddress^>^address = hostInfo->AddressList;

   // Get the alias names of the addresses in the IP address list.
   array<String^>^alias = hostInfo->Aliases;
   Console::WriteLine( "Host name : {0}", hostInfo->HostName );
   Console::WriteLine( "\nAliases : " );
   for ( int index = 0; index < alias->Length; index++ )
   {
      Console::WriteLine( alias[ index ] );

   }
   Console::WriteLine( "\nIP Address list :" );
   for ( int index = 0; index < address->Length; index++ )
   {
      Console::WriteLine( address[ index ] );

   }
}
catch ( SocketException^ e ) 
{
   Console::WriteLine( "SocketException caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
catch ( ArgumentNullException^ e ) 
{
   Console::WriteLine( "ArgumentNullException caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
catch ( NullReferenceException^ e ) 
{
   Console::WriteLine( "NullReferenceException caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
catch ( Exception^ e ) 
{
   Console::WriteLine( "Exception caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
CPP_OLD
try {
   IPHostEntry* hostInfo = Dns::Resolve(hostString);
   // Get the IP address list that resolves to the host names contained in the
   // Alias property.
   IPAddress* address[] = hostInfo->AddressList;
   // Get the alias names of the addresses in the IP address list.
   String*  alias[] = hostInfo->Aliases;

   Console::WriteLine(S"Host name : {0}", hostInfo->HostName);
   Console::WriteLine(S"\nAliases : ");
   for (int index=0; index < alias->Length; index++) {
      Console::WriteLine(alias->Item[index]);
   }
   Console::WriteLine(S"\nIP Address list :");
   for (int index=0; index < address->Length; index++) {
      Console::WriteLine(address->Item[index]);
   }
} catch (SocketException* e) {
   Console::WriteLine(S"SocketException caught!!!");
   Console::WriteLine(S"Source : {0}", e->Source);
   Console::WriteLine(S"Message : {0}", e->Message);
} catch (ArgumentNullException* e) {
   Console::WriteLine(S"ArgumentNullException caught!!!");
   Console::WriteLine(S"Source : {0}", e->Source);
   Console::WriteLine(S"Message : {0}", e->Message);
} catch (NullReferenceException* e) {
   Console::WriteLine(S"NullReferenceException 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);
}
.NET Framework Security

Platforms

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.
Version Information

.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
See Also

Reference

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