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Class (inherits from EasyUDPSocket)

AutoDiscovery uses the EasyUDPSocket class to automatically discover other Xojo applications on the network.

DataAvailable MemberJoined ReceivedMessage
Error MemberLeft SendComplete
BroadcastAddress fa-lock-32.png NetworkInterface RouterHops
Handle fa-lock-32.png PacketsAvailable fa-lock-32.png SendToSelf
IsConnected fa-lock-32.png PacketsLeftToSend fa-lock-32.png
LocalAddress fa-lock-32.png Port
Bind Poll SendMessageToIndividual
Close Purge Unregister
Connect Read UpdateMemberList
GetMemberList Register Write
JoinMulticastGroup SendMessageToGroup Write
LeaveMulticastGroup SendMessageToGroup


The AutoDiscovery class lets you automatically discover other machines on the local network that are communicating using the EasyUDPSocket class. It does so by checking to see which other applications are using the same group name that you pass to the Register function of the EasyUDPSocket class. When a member joins (this includes your application when you first call the Register method), you will get a MemberJoined event with the IP address of the member that joined. When a member leaves, then you get a MemberLeft event with their IP as well. If you would like a list of the currently connected members, you can get an array of their IPs by calling the GetMemberList method. You can refresh the list by calling the UpdateMemberList method. It clears the internal list of connected members and re-queries the network for members.

The AutoDiscovery class is intended to make communication among network users as easy as possible. To do so, it uses of a proprietary protocol. Because of this, it is unable to discover other communications protocols that may also be running on the network, such as iChat. Use the generic classes such as TCPSocket, UDPSocket, HTTPSocket, and so forth.

Sample Code

Binding to any available port between 8192 and 65535 (Note: the other member of the group must then use the same port, so you need to find a way to communicate this port to the others):

AutoDiscovery1.Bind(Rnd * (65536 - 8192) + 8192)
Loop Until AutoDiscovery1.IsConnected

Registering as a group member. Everyone on the network who wants to join the group needs to use the same group name:


Getting the member list and displaying it in a ListBox:

For Each member As String In AutoDiscovery1.GetMemberList

Leaving the group:


Sending a message to the group:

AutoDiscovery1.SendMessageToGroup(100, "Hello world")

Receiving a message using the ReceivedMessage event:

Sub ReceivedMessage (fromIP As String, command As Integer, data As String)
MessageBox(fromIP + " sent us " + command.ToString + ": " + Data)
End Sub

See Also

EasyUDPSocket, UDPSocket classes.