IPAddress.IsLoopback メソッド

.NET Framework クラス ライブラリ リファレンス

IPAddress.IsLoopback メソッド

指定した IP アドレスがループバック アドレスかどうかを示します。

名前空間: System.Net
アセンブリ: System (system.dll 内)
構文

Visual Basic (宣言)

Public Shared Function IsLoopback
 ( _
    address As IPAddress _
) As Boolean

Visual Basic (使用法)

Dim address As IPAddress
Dim returnValue As Boolean

returnValue = IPAddress.IsLoopback(address)

C#

public static bool IsLoopback
 (
    IPAddress address
)

C++

public:
static bool IsLoopback (
    IPAddress^ address
)

J#

public static boolean IsLoopback (
    IPAddress address
)

JScript

public static function IsLoopback
 (
    address : IPAddress
) : boolean

パラメータ

address

IP アドレス。

戻り値
address がループバック アドレスの場合は true。それ以外の場合は false。

解説

IsLoopback メソッドは、address と Loopback を比較し、2 つの IP アドレスが同じ場合は true を返します。

IPv4 の場合、IsLoopback メソッドは、Loopback (127.0.0.1) ではなく、127.X.Y.Z フォーム (X、Y、Z は 0 ～ 255 の値) の IP アドレスに対して true を返します。

使用例

IsLoopback メソッドを使用して、指定したアドレスがループバック アドレスであるかどうかを確認するコード例を次に示します。

Visual Basic

Imports System
Imports System.Net
Imports System.Net.Sockets

 _

Class IsLoopbackTest
   
   'Entry point which delegates to C-style main Private Function
   Public Overloads Shared
 Sub Main()
      Main(System.Environment.GetCommandLineArgs())
   End Sub
   
   
   Overloads Private Shared
 Sub Main(args() As String)
      
       If args.Length = 1 Then
         ' No parameters entered. Display program usage.
         Console.WriteLine("Please enter an IP address.")
         Console.WriteLine("Usage:   >ipaddress_isloopback
 any IPv4 or IPv6 address.")
         Console.WriteLine("Example: >ipaddress_isloopback
 127.0.0.1")
         Console.WriteLine("Example: >ipaddress_isloopback
 0:0:0:0:0:0:0:1")
         Return
      ' Parse the address string entered by the user.
      Else
        parse(args(1))
      End If 
   End Sub 'Main
   
   
   ' This method calls the IPAddress.Parse method to check whether the
 
   ' passed ipAddress parameter is in the correct format.
   ' Then it checks whether it represents a loopback address.
   ' Finally, it displays the results.
   Private Shared Sub parse(ipAdd
 As String)
      Dim loopBack As String
 = " is not a loopback address."
      
      Try
         ' Perform syntax check by parsing the address string entered
 by the user.
         Dim address As IPAddress = IPAddress.Parse(ipAdd)
         
         ' Perform semantic check by verifying that the address is a
 valid IPv4 
         ' or IPv6 loopback address. 
         If IPAddress.IsLoopback(address) And
 address.AddressFamily = AddressFamily.InterNetworkV6 Then
            loopBack = " is an IPv6 loopback address "
 + "whose internal format is: " + address.ToString()
 + "."
         Else
            If IPAddress.IsLoopback(address) And
 address.AddressFamily = AddressFamily.InterNetwork Then
               loopBack = " is an IPv4 loopback address "
 + "whose internal format is: " + address.ToString()
 + "."
            End If
         End If 
         ' Display the results.
         Console.WriteLine(("Your input address: "
 + """" + ipAdd +
 """" + loopBack))
      
      Catch e As FormatException
         Console.WriteLine("FormatException 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 'parse 
End Class 'IsLoopbackTest

C#

using System;
using System.Net;
using System.Net.Sockets;

class IsLoopbackTest
{

  private static void Main(string[]
 args) 
  {
    
    if (args.Length == 0)
    {
      // No parameters entered. Display program usage.
      Console.WriteLine("Please enter an IP address.");
      Console.WriteLine("Usage:   >ipaddress_isloopback any IPv4 or IPv6
 address.");
      Console.WriteLine("Example: >ipaddress_isloopback 127.0.0.1");
      Console.WriteLine("Example: >ipaddress_isloopback 0:0:0:0:0:0:0:1");
      return;
    }
    else
      // Parse the address string entered by the user.
      parse(args[0]);
   
  }

  // This method calls the IPAddress.Parse method to check if the 
  // passed ipAddress parameter is in the correct format.
  // Then it checks whether it represents a loopback address.
  // Finally, it displays the results.
  private static void parse(string
 ipAddress)
  {
    string loopBack=" is not a loopback address.";

    try
    {
      // Perform syntax check by parsing the address string entered
 by the user.
      IPAddress address = IPAddress.Parse(ipAddress);

      // Perform semantic check by verifying that the address is a valid
 IPv4 
      // or IPv6 loopback address. 
      if(IPAddress.IsLoopback(address)&& address.AddressFamily
 == AddressFamily.InterNetworkV6)
        loopBack =  " is an IPv6 loopback address " +
                    "whose internal format is: " + address.ToString() +
 ".";
      else
        if(IPAddress.IsLoopback(address) && address.AddressFamily
 == AddressFamily.InterNetwork)
          loopBack = " is an IPv4 loopback address " +
                     "whose internal format is: " + address.ToString() +
 ".";

      // Display the results.
      Console.WriteLine("Your input address: " + "\"" +
 ipAddress + "\"" + loopBack);
    }

    catch(FormatException e)
    {
      Console.WriteLine("FormatException 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);
    }

   }
}

C++

#using <System.dll>

using namespace System;
using namespace System::Net;
using namespace System::Net::Sockets;

// This method calls the IPAddress::Parse method to check if the
// passed ipAddress parameter is in the correct format.
// Then it checks whether it represents a loopback address.
// Finally, it displays the results.
void parse( String^ ipAddress )
{
   String^ loopBack = " is not a loopback address.";
   try
   {
      
      // Perform syntax check by parsing the address string entered
 by the user.
      IPAddress^ address = IPAddress::Parse( ipAddress );
      
      // Perform semantic check by verifying that the address is a valid
 IPv4
      // or IPv6 loopback address.
      if ( IPAddress::IsLoopback( address ) && address->AddressFamily
 == AddressFamily::InterNetworkV6 )
            loopBack = String::Concat( " is an IPv6 loopback address whose internal
 format is: ", address, "." );
      else
      if ( IPAddress::IsLoopback( address ) && address->AddressFamily
 == AddressFamily::InterNetwork )
            loopBack = String::Concat( " is an IPv4 loopback address whose internal
 format is: ", address, "." );
      
      // Display the results.
      Console::WriteLine( "Your input address: \" {0} \" {1}",
 ipAddress, loopBack );
   }
   catch ( FormatException^ e ) 
   {
      Console::WriteLine( "FormatException 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 );
   }

}

int main()
{
   array<String^>^args = Environment::GetCommandLineArgs();
   if ( args->Length == 1 )
   {
      
      // No parameters entered. Display program usage.
      Console::WriteLine( "Please enter an IP address." );
      Console::WriteLine( "Usage:   >ipaddress_isloopback any IPv4 or IPv6
 address." );
      Console::WriteLine( "Example: >ipaddress_isloopback 127.0.0.1"
 );
      Console::WriteLine( "Example: >ipaddress_isloopback 0:0:0:0:0:0:0:1"
 );
   }
   else
      parse( args[ 1 ] );

   
   // Parse the address string entered by the user.
}

J#

import System.*;
import System.Net.*;
import System.Net.Sockets.*;

class IsLoopbackTest
{
    public static void main(String[]
 args)
    {
        if (args.length == 0) {
            // No parameters entered. Display program usage.
            Console.WriteLine("Please enter an IP address.");
            Console.WriteLine(
                "Usage:   >ipaddress_isloopback any IPv4 or IPv6 address.");
            Console.WriteLine("Example: >ipaddress_isloopback 127.0.0.1");
            Console.WriteLine(
                "Example: >ipaddress_isloopback 0:0:0:0:0:0:0:1");
            return ;
        }
        else {
            // Parse the address string entered by the user.
            Parse(args[0]);
        } 
    } //main
    
    // This method calls the IPAddress.Parse method to check if the
 
    // passed ipAddress parameter is in the correct format.
    // Then it checks whether it represents a loopback address.
    // Finally, it displays the results.
    private static void
 Parse(String ipAddress) 
    {
        String loopBack = " is not a loopback address.";
        try {
            // Perform syntax check by parsing the address string
            // entered by the user.
            IPAddress address = IPAddress.Parse(ipAddress);
                
            // Perform semantic check by verifying that the address
 is a valid
            // IPv4 or IPv6 loopback address. 
            if ( IPAddress.IsLoopback(address) && address.get_AddressFamily().
                Equals(AddressFamily.InterNetworkV6)) {
                loopBack = " is an IPv6 loopback address "
                    + "whose internal format is: " + address.ToString()
 + ".";
            }
            else {
                if (IPAddress.IsLoopback(address) && 
                    address.get_AddressFamily().Equals
                    (AddressFamily.InterNetwork)) {
                    loopBack = " is an IPv4 loopback address " 
                        + "whose internal format is: " + 
                        address.ToString() + ".";
                }
            }
              // Display the results.
            Console.WriteLine(("Your input address: " + "\""
 
                + ipAddress + "\"" + loopBack));
        }
        catch (FormatException e) {
            Console.WriteLine("FormatException 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()));
        }
    } //Parse
} //IsLoopbackTest

プラットフォーム

Windows 98, Windows 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

開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。

バージョン情報

.NET Framework
サポート対象 : 2.0、1.1、1.0
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
IPAddress クラス
IPAddress メンバ
System.Net 名前空間