BeginJoinGroup Method

UdpAnySourceMulticastClient.BeginJoinGroup Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Binds the socket and begins a join operation to the multicast group to allow datagrams to be received from any group participant.

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

public IAsyncResult BeginJoinGroup(
	AsyncCallback callback,
	Object state


Type: System.AsyncCallback
A callback method to invoke when the operation completes.
Type: System.Object
Optional state information to pass to the callback method for this operation.

Return Value

Type: System.IAsyncResult
An IAsyncResult that references this operation.


The multicast group has already been joined or a join operation is currently in progress.


The UdpAnySourceMulticastClient has been disposed.


An error occurred when attempting to access the socket. See the Remarks section for more information.

The BeginJoinGroup method binds a UDP multicast socket to a local port and joins a multicast group to allow datagrams to be received from any multicast group participant. The local port and multicast group address are specified in the UdpAnySourceMulticastClient constructor.

The method specified in the callback parameter is invoked when the operation to join the multicast group has completed.

If required by the runtime, the BeginJoinGroup method also performs a policy check to verify that the client is allowed to access the multicast group. If the client is not allowed access, a SocketException is thrown with SocketError.AccessDenied.

Version Notes

Windows Phone

In Windows Phone applications, this method will successfully complete when the device running the application is connected to a wireless network, or if you are debugging with the emulator running on a computer connected to the Internet. If you call BeginJoinGroup when the device is connected to a cellular network only, a SocketException will occur.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Windows Phone

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