MulticastOption Class

 

Contains IPAddress values used to join and drop multicast groups.

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

System::Object
  System.Net.Sockets::MulticastOption

public ref class MulticastOption 

NameDescription
System_CAPS_pubmethodMulticastOption(IPAddress^)

Initializes a new version of the MulticastOption class for the specified IP multicast group.

System_CAPS_pubmethodMulticastOption(IPAddress^, Int32)

Initializes a new instance of the MulticastOption class with the specified IP multicast group address and interface index.

System_CAPS_pubmethodMulticastOption(IPAddress^, IPAddress^)

Initializes a new instance of the MulticastOption class with the specified IP multicast group address and local IP address associated with a network interface.

NameDescription
System_CAPS_pubpropertyGroup

Gets or sets the IP address of a multicast group.

System_CAPS_pubpropertyInterfaceIndex

Gets or sets the index of the interface that is used to send and receive multicast packets.

System_CAPS_pubpropertyLocalAddress

Gets or sets the local address associated with a multicast group.

NameDescription
System_CAPS_pubmethodEquals(Object^)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_protmethodFinalize()

Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_protmethodMemberwiseClone()

Creates a shallow copy of the current Object.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

Use a MulticastOption to store the IPAddress of a multicast group you want to join or drop. Use the Socket::SetSocketOption method with the following parameters to join a multicast group.

Parameter

Value

socketOptionLevel

SocketOptionLevel::Udp

socketOptionName

AddMembership

object

MulticastOption

Use DropMembership to drop a multicast group.

The following examples join the default IP interface to an IP multicast group. They assume the IP multicast group address in the range 224.0.0.0 to 239.255.255.255.

#using <System.dll>

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

// This program shows how to use the MultiCastOption type. In particular,
// it shows how to use the MultiCastOption(IPAddress, IPAddress) constructor,
// You need to use this constructor, in the case of multihomed host (i.e.,
// a host with more than one network card). With the first parameter you
// specify the multicast group address, with the second you specify the
// local address of one of the network cards you want to use for the data
// exchange.
// You must run this program in conjunction with the sender program as
// follows:
// Open a console window and run the listener from the command line.
// In another console window run the sender. In both cases you must specify
// the local IPAddress to use. To obtain this address run the ipconfig from
// the command line.
//
public ref class TestMulticastOption
{
private:
   static IPAddress^ mcastAddress;
   static int mcastPort;
   static Socket^ mcastSocket;
   static MulticastOption^ mcastOption;

   static void MulticastOptionProperties()
   {
      Console::WriteLine( "Current multicast group is: {0}", mcastOption->Group );
      Console::WriteLine( "Current multicast local address is: {0}", mcastOption->LocalAddress );
   }


   static void StartMulticast()
   {
      try
      {
         mcastSocket = gcnew Socket( AddressFamily::InterNetwork,SocketType::Dgram,ProtocolType::Udp );
         Console::Write( "Enter the local IP Address: " );
         IPAddress^ localIPAddr = IPAddress::Parse( Console::ReadLine() );

         //IPAddress localIP = IPAddress::Any;
         EndPoint^ localEP = dynamic_cast<EndPoint^>(gcnew IPEndPoint( localIPAddr,mcastPort ));
         mcastSocket->Bind( localEP );

         // Define a MuticastOption object specifying the multicast group
         // address and the local IPAddress.
         // The multicast group address is the same one used by the server.
         mcastOption = gcnew MulticastOption( mcastAddress,localIPAddr );
         mcastSocket->SetSocketOption( SocketOptionLevel::IP, SocketOptionName::AddMembership, mcastOption );

      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( e );
      }

   }

   static void ReceiveBrodcastMessages()
   {
      bool done = false;
      array<Byte>^bytes = gcnew array<Byte>(100);
      IPEndPoint^ groupEP = gcnew IPEndPoint( mcastAddress,mcastPort );
      EndPoint^ remoteEP = dynamic_cast<EndPoint^>(gcnew IPEndPoint( IPAddress::Any,0 ));
      try
      {
         while (  !done )
         {
            Console::WriteLine( "Waiting for Multicast packets......." );
            Console::WriteLine( "Enter ^C to terminate." );
            mcastSocket->ReceiveFrom( bytes, remoteEP );
            Console::WriteLine( "Received broadcast from {0} :\n {1}\n", groupEP, Encoding::ASCII->GetString( bytes, 0, bytes->Length ) );
         }
         mcastSocket->Close();
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( e );
      }

   }


public:
   static void Main()
   {

      // Initialize multicast address group and multicast port.
      // Both address and port are selected from the allowed sets as
      // defined in the related RFC documents. These are the same values
      // used by the sender.
      mcastAddress = IPAddress::Parse( "224.168.100.2" );
      mcastPort = 11000;

      // Start a multicast group.
      StartMulticast();

      // Display multicast option properties.
      MulticastOptionProperties();

      // Receive brodcast messages.
      ReceiveBrodcastMessages();
   }

};

int main()
{
   TestMulticastOption::Main();
}

#using <System.dll>

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

// This is an auxiliary program to be used in conjunction with a listener
// program.
// You must run this program as follows:
// Open a console window and run the listener from the command line.
// In another console window run the sender. In both cases you must specify
// the local IPAddress to use. To obtain this address run the ipconfig
// from the command line.
//
ref class TestMulticastOption
{
private:
   static IPAddress^ mcastAddress;
   static int mcastPort;
   static Socket^ mcastSocket;
   static void JoinMulticast()
   {
      try
      {

         // Create multicast socket.
         mcastSocket = gcnew Socket( AddressFamily::InterNetwork,SocketType::Dgram,ProtocolType::Udp );

         // Get the local IP address used by the listener and the sender to
         // exchange data in a multicast fashion.
         Console::Write( "\nEnter local IPAddress for sending multicast packets: " );
         IPAddress^ localIPAddr = IPAddress::Parse( Console::ReadLine() );

         // Create an IPEndPoint Object*.
         IPEndPoint^ IPlocal = gcnew IPEndPoint( localIPAddr,0 );

         // Bind this end point to the multicast socket.
         mcastSocket->Bind( IPlocal );

         // Define a MuticastOption Object* specifying the multicast group
         // address and the local IPAddress.
         // The multicast group address is the same one used by the listener.
         MulticastOption^ mcastOption;
         mcastOption = gcnew MulticastOption( mcastAddress,localIPAddr );
         mcastSocket->SetSocketOption( SocketOptionLevel::IP, SocketOptionName::AddMembership, mcastOption );
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( "\n {0}", e );
      }

   }

   static void BrodcastMessage( String^ message )
   {
      IPEndPoint^ endPoint;
      try
      {

         //Send multicast packets to the listener.
         endPoint = gcnew IPEndPoint( mcastAddress,mcastPort );
         mcastSocket->SendTo( ASCIIEncoding::ASCII->GetBytes( message ), endPoint );
         Console::WriteLine( "Multicast data sent....." );
      }
      catch ( Exception^ e ) 
      {
         Console::WriteLine( "\n {0}", e );
      }

      mcastSocket->Close();
   }


public:
   static void main()
   {

      // Initialize multicast address group and multicast port.
      // Both address and port are selected from the allowed sets as
      // defined in the related RFC documents. These are the same values
      // used by the sender.
      mcastAddress = IPAddress::Parse( "224.168.100.2" );
      mcastPort = 11000;

      // Join the listener multicast group.
      JoinMulticast();

      // Broadcast message to the listener.
      BrodcastMessage( "Hello multicast listener." );
   }

};

int main()
{
   TestMulticastOption::main();
}

.NET Framework
Available since 1.1

Any public static ( Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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