UdpClient.JoinMulticastGroup Method (IPAddress, IPAddress)

 

Adds a UdpClient to a multicast group.

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

public void JoinMulticastGroup(
	IPAddress multicastAddr,
	IPAddress localAddress
)

Parameters

multicastAddr
Type: System.Net.IPAddress

The multicast IPAddress of the group you want to join.

localAddress
Type: System.Net.IPAddress

The local IPAddress.

Exception Condition
ObjectDisposedException

The underlying Socket has been closed.

SocketException

An error occurred when accessing the socket. See the Remarks section for more information.

Before you join a multicast group, be sure that the socket is bound to the port or endpoint. You can do this by calling one of the constructors that accepts a port or an endpoint as parameter.

System_CAPS_noteNote

There are several multicast address ranges to choose from. You can find them in the IETF RFC 2375.

System_CAPS_noteNote

You cannot call JoinMulticastGroup on a UdpClient constructed without a specific local port (that is, using the UdpClient() or UdpClient(AddressFamily) constructor).

The following code example shows the use of the JoinMulticastGroup method.

// Subscribe to a multicast group.
public static void DoJoinMulticastGroup(UdpClient u, string mcast)
{
    IPAddress[] multicastAddress = Dns.GetHostAddresses(mcast);

    u.JoinMulticastGroup(multicastAddress[0]);
    Console.WriteLine("Joined multicast Address {0}",
        multicastAddress[0]);
}

.NET Framework
Available since 2.0
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