IPAddress.IsLoopback メソッド

2008-03-28

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。

Public Shared Function IsLoopback( _
   ByVal address As IPAddress _) As Boolean
[C#]
public static bool IsLoopback(IPAddressaddress);
[C++]
public: static bool 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 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

[Visual Basic, C#, C++] IsLoopback プロパティを使用して、指定したアドレスがループバックアドレスかどうかを確認する例を次に示します。

 
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 <mscorlib.dll>
#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=S" 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(S" is an IPv6 loopback address whose internal format is: ", address, S".");
      else
         if (IPAddress::IsLoopback(address) &&
            address->AddressFamily == AddressFamily::InterNetwork)
            loopBack = String::Concat(S" is an IPv4 loopback address whose internal format is: ", address, S".");

      // Display the results.
      Console::WriteLine(S"Your input address: \" {0} \" {1}", ipAddress, loopBack);
   } catch (FormatException* e) {
      Console::WriteLine(S"FormatException 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() {
   String* args[] = Environment::GetCommandLineArgs();
   if (args->Length == 1) {
      // No parameters entered. Display program usage.
      Console::WriteLine(S"Please enter an IP address.");
      Console::WriteLine(S"Usage:   >ipaddress_isloopback any IPv4 or IPv6 address.");
      Console::WriteLine(S"Example: >ipaddress_isloopback 127.0.0.1");
      Console::WriteLine(S"Example: >ipaddress_isloopback 0:0:0:0:0:0:0:1");
   } else
      // Parse the address string entered by the user.
      parse(args[1]);
}

[JScript] JScript のサンプルはありません。Visual Basic、C#、および C++ のサンプルを表示するには、このページの左上隅にある言語のフィルタボタンをクリックします。

必要条件

プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET, Common Language Infrastructure (CLI) Standard

参照

IPAddress クラス | IPAddress メンバ | System.Net 名前空間

次の方法で共有

IPAddress.IsLoopback メソッド

パラメータ

戻り値

解説

使用例

必要条件

参照

その他のリソース